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MANUAL

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COMPLETE

MANUAL
Updated and Expanded
Illustrations by
LEONELLO CALVETTI, RON CARBONE ,
PAUL DIMARE, STEVE KARP, DON MANNES ,
RUSSELL J. VON SAUERS AND JEFF TRISH
HEARST BOOKS
A Division of Sterling Publishing Co. , Inc.
NEW YORK

COMPLETE CAR CARE MANUAL
Updated & Expanded
Copyri ght © 2003, 2005 by
H earst Communications, Inc.
All rights reserved. The written instructions, illustrations,
and photographs in this volum e are intended for the
personal use of the rea der and ma y be reproduced for
that purpose only. Any other use, especia lly commercial
use, is forbidden under law witho ut the wr itten
permission of the copyright hold er.
Eve ry effort has bee n made to ensure that a ll the
in fo rmation in this book is accurate. However, du e
to differing conditio ns, tools, and indi vidual skills,
the publisher cannot be respo nsible for any injuries,
losses, and/o r other damages that ma y result frol11 the
use of th e information in this book.
Produced by Bi shop Books
777 Westchester Avenue, Su ite 100
White Pl a ins, New York 10604
Th e Library of Congress has cata loged the first hardcover edition as follows:
Popular mechanics comp lete car care manua l /
Illustration s by Russel]. Von Sauers,
Ron Carbon e, and Don Mannes.
p. cm.
ISBN 1-588 16-260-5
1. Automob il es-Maintenance and repairAmate urs' manu a ls. I. Popular mechanics.
TL152.P625 2003
629.28'72-dc21
2003050841
10 9 8 7 6 5 4 3 2 1
Published by H earst Books
A Division of Ster lin g Publishin g Co., Inc.
387 Park Avenue South, New York, NY 10016
Popul ar Mechanics is a trademark owned by
H earst Magazines Propert y, Inc., in USA, and H ea rst
Comm unications, Inc., in Canada. Hearst Books is a
trademark owned by Hearst Communications, In c.
www. popularm echanics.com
For info rmati on about cu stom editions, specia l
sa les, premium and corporate purch ases, p lease
contact Sterling Special Sa les Department at
800-805-5489 or specialsa les@sterlingp ub. com.
Di stributed in Canada by Sterling Publishing
G/o Canadian Manda Group, 165 Dufferin Street
Toronto, Onta rio, Ca nada M6K 3H6
Di stributed in Austra li a by
Caprico rn Link (A ustrali a) Pty. Ltd.
P.O. Box 704, Windsor, N SW 2756 Austra li a
Manufactured in China
ISBN 1-588 16-439-X

Contents
Maintenance Basics

2

88
138
158
214

Engine

Drivetrain

Electrical and Electronic Systems

Chassis

Interior and Exterior

Appendix

I

'--

254

314

Foreword

or almost 100 years, the editors of Popular Mechanics have made car care and maintenance
a central component of the magazine . From the very beginning, we understood just how passionate readers were abou t their cars, and just how far they would go to protect, repair, and
maintain their beloved vehicles . How else to explain an exec uti ve trad ing in his workday suit for a
pair of overalls and spending his Saturday afternoons hunkered down under the hood of his car?
For some of our readers, saving money is no doubt a major motivation . But for most, working on
their cars is a labor of love, pure and simple. That, and they want to make sure the repair is done
right. The cars may have changed over the years, but the dedication of readers has been a constant.
And Popular Mechanics has been a partner all the way, delivering the hand s-on information car
enthu siasts need to get the job done right.
We understand th at the key to any successful piece of advice is clarity. So we strive to make sure
o ur instructions and our illustrations are legible and to the point. We hope yo u'll find those qualities in evidence in the pages that follow. You'll find chapters on all the basic car componentsengine, chassis, electrica l system, drive train, and interior/exterior-as we ll as an opening chapter on
the essential maintenance information that every owner sho uld know. Each project is la beled
"easy," " modera te," or "d iffic ult " to allow yo u to make yo ur own decision as to whether yo u have
the requisite expertise, not to mention the time and energy, to undertake a given procedure. So,
whether yo u're breaking out the brand-new wrenches from your first tool set, or sliding under a car
on yo ur creeper for the umpteenth time, yo u'll find this book to be an indispensable reference
source, packed with easy-to-fo llow, step- by-s tep instructions that take the mystery ou t of auto
maintenance and save yo u money. And , should yo u decide that a given repair is a bit too tr ick y for
you, the book will arm yo u with the knowledge necessary to discuss the work intelligently with
your professional mechanic.
Our goal is a simple one: We want to provide yo u with the information yo u need to keep that
treas ured car of yo urs in peak condition regardless of its make, model, or age . We know how much
yo u love yo ur car and how dedicated yo u are to maintaining it. We're hoping our book provides
you with a way to put that dedication into action .

F

THE ED ITORS

Popular Mechanics

1

2

CHAPTER ONE

Replacing Wiper Blades / 4
Replacing Your Air Filter / 7
Changing a Tire / 10
Replacing Your Tailpipe / 13
Repairing Power Antennas / 16
Replacing Your Spark Plugs / 19
Replacing Spark Plug Wires / 21
Maintaining Your Tires / 24
Jumpstarting Your Car / 27
Repairing a Leaky Radiator / 30
Curing Pulsing Brakes / 34
Getting Your Car Ready For Winter / 37
Repairing a Flat Tire / 40
Servicing Your AlC / 44
Maintaining Your Battery / 48
Replacing a Battery / 51
Maintaining and Repairing
Your Suspension / 54
Replacing Shock Absorbers / 58
Maintaining Your Exhaust System / 62
Replacing Your Belts / 65
Replacing Hood and Hatch Struts / 69
Resetting Your Emissions Maintenance
Reminder (EMR) / 73
Passing an Emissions Inspection / 76
Changing Your Oil and Filter / 79
Search Engines / 82
Charging Your Battery / 85

3

EASY

Replacing Wiper Blades

hro ugh the monsoonli ke ra in ,
yo u see some sort of flashing
lights ahead of yo u. But despite
the best efforts of your w indshi eld
wipers, all yo u can see are blurry blo bs
of ye ll ow, am ber and red. Slow ing to
half speed, yo u continue to press fo rwa rd thro ugh the deluge. Sudd enly
yo u rea lize that those fl as hing blo bs
are the warning lights of a sto pped
school bus, and children are running
across the road in front of yo u. Fortu nately, your brakes work infinitely better than yo ur windshi eld wipers.

T

4

Once it's dry and sunn y aga in, grab
a tape measure and hea d for the garage.
Lift one of the wiper arms (it's usually
easier to grab the driver's-side arm ) off
the windshield against its spring tension and keep lifting unti l the pivot
point locks the arm upright (Fig. 1) .
Look for contaminated rubber
inserts, which can be ca used by road
film or ca r-was h chemica l adhesion.
Inspect the wiping edges for "park set
rubbel;" the term used to describe hardened finely-cracked inserts that have
been exposed to the sun too long in a

(Fig. 1) In 10 minutes, you can replace
your streaky view of the world through
a windshield with fresh wiper blades.

parked position. This will cause chattering and skipping. Check for a rubber
insert that has been partially torn away
fro m its metal sup port. It will slap the
windshield with each wiping pass.
Pla in o ld dr ied o ut, cracked rubber
inserts mea n they've seen better days .
Yo u a lso may find rub ber inserts that
are a brasio n-worn from w inter co ndi ti ons, in frequ ent car washes and/or a

MA I NTENANCE

BASICS

HOW IT WORKS

Windshield Wipers

(Fig. 2) Measure your old blades before
heading down to the parts store.

lack of preventive maintenance. And
rear-wind ow wiper blades are subjected to a lot more roa d grit than
front blades. In th e rear, you get aerodynamic backwas h, with th e rear tires
kicking up a ll sorts of debris. And
do n't rul e out an improperl y insta ll ed
refi ll. Maybe someo ne else had tried
to replace the in serts before yo u got
to them . Bu y a pair of full-bl ade
assemblies to get a fac tory fit. Also
check the wiper anTIs. If they're okay,
proceed to replace the blades .

Blade Runner
But first, measure the length of the
wiper blade to the nearest inch (Fig. 2) .
Most vehicles today use blades anywhere from about 16 to 21 in. in
length. H owevel; so me cars or minivans w ith very large windshields may
exceed that by a few inches.
Parts ca ta logs, even those for simp le items li ke w iper blades, are fu ll of
all sorts of extraneo us information.
You may find three different types of
re fills and three different types of
blades for almost every vehicl e listed .

REPLACING WIPER BLADES

As the rubber insert of a wiper
blade sweeps across your wet windshield, a wedge of water builds up
in front of the rubber-a squeegee
effect-and the wiper displaces
that water elsewhere_ What's left is
clean, clear glass that allows you to
continue on your way safely_ That's
the way it's supposed to work. The
illustrations to the right show some
of the reasons why it may not.
Other reasons may involve components that work behind the
scenes-actually, behind the cowl
or dashboard of your car. They
include the splined shafts that the
wiper arms pivot on, the mechanism
that creates the back-and-f orth pivoting motion and the electric wiper
motor that drives the whole system.
A small nut under a cosmetic
plastic cover jams the wiper arm
onto the splines of its shaft. The
splines keep the shaft from slipping
in the arm as it turns in one direction and then the other, over and
over and over. This reciprocating
motion is created by a metal cranktype linkage assembly that's
attached to each wiper arm's
splined shaft, and to the wiper
motor with another splined shaft.
Picture the chugging action of a
steam locomotive's piston and drivewheels and you 'll get the idea.
Rear wipers-found on minivans,
SUVs and some sport coupes-work
the same way, except the reciprocating mechanism is much smaller
and built into the motor.
Wiper speed depends on the
amount of voltage that's sent to the
motor from the wiper switch-low
voltage equals low speed, high voltage equals high speed. Intermittent
wiper action is created by a separate electronic module wired
between the switch on your dashboard or steering column st alk and
the motor. Some cars even have
electronically controlled roadspeed-sensitive wipers that wipe
faster the quicker you go.

TORN RUBBER

PARK SET RUBBER

DAMAGED SUPERSTRUCTURE

ABRASION-WORN RUBBER

5

(Fig. 3) Release the tab to disengage the
the straightened arm.

If yo u do n 't kn ow w ha t bra nd of
bl ade your ca r has, do n't bu y r ubber
insert refi ll s. The refi ll s may not fit the
bl ades properl y, and yo u' ll get lo usy
wiper p erfo rmance .
If yo u do kno w w ha t bra nd of
bl ade is currentl y o n th e car, refill s are
okay as lo ng as yo u bu y th e sa me
bra nd a nd type. Experi ence has
shown that m ixing bl ade and refi ll
bra nd s doesn't lea d to o ptimulll w iper
performa nce. But rea listica ll y, yo u're
still better off just buying a p a ir o f
bl ade asse m bli es no ma tter w ha t t he
bra nd . Th e few extra bu cks get yo u
new, ma tched co mpo nents th at
mo unt q ui ck ly a nd eas il y.

Fresh Rubber
Now that yo u've got new bl ades in
ha nd , it's tim e to determine w hat
method to use to mo unt th e w iper
blade to th e wiper ar m. T here a re
ma ny varia ti o ns: hook-s lot conn ecto r,
pin -type a rm , wide-stra ight end , na rrow-s traight end , side sa ddl e, pin-type
bl ade, narrow-dea d loc ke r, fla t hook
a nd rock to lock.
At the very least, yo u'll need a
sm a ll screwd r iver to gentl y p ry t he
blade off th e arm o r to unl ock a ta b
of so me sort. Som etim es a pa ir of
needl e- nose pli ers helps too, but th e
pli ers tend to ma r the w iper-arm fi nish mo re th a n a screwdr iver.
Bear in mind that m ost wipers will
stay ra ised in an upright positio n away
from the w indshield so yo u ca n work

6

unit may simply lock o nto the pin.
o n them. O thers w ill not.
Sometim es, the box w ill contain an
So if thi s is th e case, yo u'll
adapte r that locks in to t he blade op enha ve to ho ld the bl ade off
ing and accepts pins in di fferent sizes .
the glass w hile yo u wo rk .
T he stra ight-en d connector ca n be
If yo ur ca r has w ipers tha t
tricky. So metimes yo u need to lift a
park behind a cow l or the
ta b o n top o f the existing blade with a
lip of the hood, turn on the
ignitio n, turn on th e wipers screwdri ver to clear the lock ing nub
o n the a rm . Yo u m ay also need to
and then shut off the igni cock t he o ld bl ade a few degrees o utti on when the w ipers are in
o f-pa ra ll el w ith t he a rm to slide it off
mid stro ke so yo u ca n have
t he arm 's end .
access to them.
Once th e old bl ade is off, ap plying
Al ways r em e mber to
a little a nti seize co mpo und to th e
lay a cl ea n rag o n to p o f
ar m's end couldn 't hurt. The new
the w ind shield to p ro tect
bl ade m ay come w ith a n adap ter to fit
blade from
the glass in ca se th e ba rethe a rm 's end o r it may just slide o n .
meta l w iper a rm su d Aga in , give a firm shove until th e
denl y snaps do wn o n th e
blade cli cks in to place.
w inds hi eld 's glass.
If yo u' re replacing a rubber insert,
For the hook-s lot co nnector, yo u
just grab it with needle-nose pliers at the
generally need to raise the arm off the
open end . T he other end genera lly has
windshield to a working height. T hen ,
some sort of deadstop that prevents the
swing the blade perpendicular to the
insert fro m sliding o ut. Yo u may need
arm so tha t you have more light on the
connecto r. Yo u'll find some sort of ta b
to unlock a ta b o r squeeze together the
locking ta ngs of the in se rt before yo u
at the connector that either needs to be
lifted or pushed to release the lock that
ca n begin pulling. Th en, just ho ld the
holds the blade p ivot in the hook slot.
blade firm ly w hil e yo u pull th e insert
O nce the ta b is released, a firm shove
o ut like a p iece of sp ag hetti. Gra b th e
new insert-m a ke sure that yo u've got
to wa rd the base of the a rm will slide
the blade right out of the hook slot
the right end if they're different-line
(Fig. 3) . Then, simpl y line up the new
it up w it h the fi rs t set of g uides o n the
bl ade's mo unt (there may be a n adapter
bl ade, th en fee d it in ca refull y. Ma ke
sure to engage eac h set of g uides as
in the box to crea te this mo unt ) w ith
the hook slot and sli de it in until it
yo u go. Sometimes t here are as ma ny
clicks. This mea ns it's locked in place.
as eight guides . O nce th e in se rt is a ll
Fo r the pin-type a rm , ra ise th e arm
the way in , make sure it is locked in
p lace. fj
to a working height and ta ke a close
look a t the type of lock(Fig. 4) With pin-type wiper blades, push down on the
ing ta b th at holds the
pin lock to release the wiper blade from the wiper arm
bl ade o nto the p in.
with a sideways motion.
Yo u'll either have to
p ush the ta b up fro m
undern ea th the bl ade o r
Iift the ta b from th e top
wi th a screwdri ve r (Fig.
4) . Once th e tab
" unco llars" the pin ,
p ull the blade assembl y
with a sid eways m otio n
away fro m the a rm. (Try
to imagine p ulling t he
blade up the w indshield,
to picture th e motio n. )
Depending on the bl ade
manufacturer, the new

MAINTENANCE

BASICS

l

~ EA__S_Y__________

--------

~--------------------------------------------------------------------1

Yo ur mil eage has been dropp in g
stead ily for mo nths. A tun eup is in
order, so a fin e Sa turd ay morn ing
find s yo u on a deserted stretch of
roa d . Yo u fig ure a few miles of sp irited dri ving should blowo ut tb e cobwe bs a nd restore tha t ponycar performance. Bu t w hat happe ns in stead is a
lot of no ise a nd no t much performa nce a t a ll . Time to check th e air
cl ea ner-w hi ch is p lugged w it h d irt,
bugs a nd lea ves .
Every engine ha s an a ir fi lter, a nd
althoug h t here have been ma ny types
of air-fi lter ing materials tried over

REPLACING

YOUR

AIR

FILTER

t he years-in cluding o il -we tted plastic foa ms a nd w ire m es h-dr y,
p lea ted "paper" (actu all y res inimpregnated , hea t-cured fiber ) co ntinu es to be t he mater ia l of cho ice
for filter elem ents in eve ryt hin g from
cars to heavy-duty trucks a nd offroad equip ment .

Housing Project
C hec k yo u r a ir filte r at leas t o nce a
yea r. All air-filte r ho usin gs are
so mewhe re und e r the hoo d (Fig. 1) .
The housing cover ma y be held by
w ingnuts or spr ing clips- prett y

(Fig. 1) Check your old filter element
for dirt, oil or moisture, cracks and
proper sealing at the gasket.

stra ightforward stuff. Separa te the
cove r from the hous ing a nd yo u ca n
li ft t he filter o ut for inspec ti on.
Ma ny fil te rs, particu lar ly t he na rrow cyli nd ers use d o n o lde r rea rdr ive ca rs a nd eve n on many of
toda y's tru cks, ca n be rotated. If
th e re's a dirt y area nea r th e a ir
intake , tap th e filter agains t a ta ble
to remove loose dirt, then turn it
0
180 and expose a fresh surface t~

I

7

(Fig. 2) If a conical filter
has a dirt buildup on only
half the circumference, it
can be rotated 1800 to
equalize dirt pickup,
extending service life.
Clean the housing's interior before assembly.

th e a ir inta ke (Fig. 2) . So m e con ica l
fil te rs a lso can be r o ta ted , but o t hers
ca n 't. Neve r tr y to clean a "paper"
a uto motive filter in detergent a nd
wa ter. So m e hea vy-duty filter s a re
d esigned to be cl ean ed severa l times,
but a utom o t ive filters are not.
Before yo u reuse a fi lter, ho weve r,
in sp ect it fo r crac ked p lea ts. Th e best
way is to hold th e dirty sid e of th e fi lter in fr o nt of yo ur eyes with good
lighti ng on the oppos ite sid e (w ith a
cylindrica l fi lter, ho ld a troub le li ght
in the middle of the openin g). O f
co urse, yo u shou ld see some tra nslucence (if yo u do n't, the filter is
p lugged ). But if yo u see even a single
li ne of li ght, w hich ind ica tes a ha irline crac k, discard t he fi lter. A lo t of
unfiltered a ir ca n get t hro ugh a c rack,
a nd it's the a bras ive d ust in th e air
t hat wears engines . Sure, that wea r
ta kes p lace over time, but if yo u're in
a du sty area th a t time ca n be a lo t
sho rter th a n yo u'd li ke.
Buy a q uality rep lace ment fil te r.
T he top bra nd s are d iffere nt fro m th e
no-nam e cheapies yo u may see. There
a re ma ny grades of fi lter " p aper " a nd
th e m o re expensive ones used by th e
to p bra nd s have more consistent

po res, so they do a better jo b of t ra pp ing dirt. In additi o n, their p lea ts are
more prec ise ly spaced so the fi lter has
t he maxim um surface area fo r th e size
of t he ho using.

Metering the Air
Ju st downstream of t he filter ho usin g,
perha ps conn ected by a duct, w ill be
the engin e's a irfl ow meter, or sensor.
(So me engines have no airflow meter.
Instea d, their computer calcu la tes air
intake using rpm , intake vac uum a nd
baro metri c press ure.) Conta min ati on
of the a irflow meter w ill give yo ur
engine's co mp uter inacc ura te in forma ti o n a bo ut the a mou nt (mass) of
a ir the engin e is burnin g. Th a t coul d
mea n poo r d rivea bility, p oo r m ileage
a nd hard sta rting.
Don 't, however, tr y to clea n th e
a irflo w se nsor, save fo r blo w in g
loose d irt a nd co bwebs wi th yo ur
brea t h. T he ca libra tio n of th ese
in stru ments is fr ag il e, a nd yo u sta nd
a good cha nce of muc kin g yo ur sensor up irrepa ra bly.

Duct Hunting
Before yo u install the new fi lter,
in spect the duct fr om the th ro ttle

body to t he fi lter ho using. Sprea d the
flu tes of t he du ct, look in g fo r cracks.
If th e d uct is cracked, it may be closed
a t idle but sprea d o n acce leration,
w hen t he engine torq ues. Th at not
o n ly brin gs in unfi lte red air, but o n
today 's engines with m ass a irfl ow senso rs, the dirty a ir also is " unmea sured ." T he am o unt of fuel sprayed
by the inj ectors is determin ed by how
much a ir is fl ow ing in , so if some of
t ha t a irfl ow isn't meas ured by the senso r, not eno ug h fuel w ill be inj ected .
T he engine w ill run lea n and hesita te
and/or stum ble . Th e sam e th ing ca n
occur if th e d uct isn 't properly fitted
a nd cla mped a t each end .
Find a crack ? Well , it's a duct, so yo u
ca n repa ir it w ith duct tape (Fig. 3) .
Th at's a move that no professiona l
would ma ke, beca use in time th e tape
w ill lose its grip in the hea t of the
engine co mpartment, as the duct
flexes. Bu t it's your cal; and if yo u a re
w illing to rec heck periodica ll y a nd
retape as necessary, yo u ca n save the
cost of th e new pa rt, or a t least postpone the expense.

Fit Is Important
Ca refull y ch eck th e fit betwee n th e
lips of th e ho using a nd the rubber
ga sket rimm ing th e filter. Thi s gas ket
no t o nl y sea ls the filter ho usin g's tw o
ha lves togeth er, but a lso p rov id es a n
a irtight a nd dirt-ti g ht sea l betwee n
th e fil ter a nd the cl ea n sid e of th e
ho using . Look carefully a t th e old filter's gasket. It sho uld show a
smo ot h , cl ea n line 360 ar o und a t
the sea ling fa ce o n bo th sid es. The
rim of th e filter ho using w ill have
co mpressed th e rubber gas ket if
every thin g is correct . If no t, a little
detecti ve wo rk is in o rd er. Is t he fil ter
the co rrect pa rt ? If not , is yo ur
replacem ent fil ter th e co rr ect p a rt?
D on't re ly o n just a visual compariso n-l oo k up th e correct pa rt number a nd cross-refe rence. Ad it 's p oss ible a no t her bra nd w ill fit better.
Are a ll of th e sp ring cl a m ps p ro perl y latched ? So me air cl ea ners use
screws to hold them shut, whi le others use a large w ingnut. All of the fa steners need to be ti ght, even that one
0

MAINTENANCE BASICS

8

(Fig. 3) Check the air cleaner 's
ductwork for leaks and splits, especially if you 're having driveability
problems. Temporary repairs can be
made with ordinary duct tape.

DUCT TAPE

byp ass th e f ilter and a llow dirt into
the engin e.

Buttoning Up

yo u can hardl y see or reach next to
th e battery. On a few ve hicles, the
ho us ing is attached by a bo lt or spring
clamp that can be removed to a ll ow
the hous ing to be di splaced an inch or
two, permitting big hands to fit into a
na rrow space.
Rea d y to install the filter element ?
C lea n out th e housi ng first , wi ping

th e inn er surface w ith a cloth lig htl y
m o istened w ith solve nt. In sert the
element so it seats properl y. A filte r
has a specific side up or toward the
throttle bod y, and yo u h ave to in stal l
it correc tl y so the e nd seal lines up
w ith the shape of the hou sing or its
cover. If it doesn't, yo u won't get a
good end sea l, and incom ing air ma y

It's time to fini sh up. In sta ll th e cove r
or th e ha lves of t he filter hou sin g. In
additi o n to the sprin g clips a nd
w ingnurs that ho ld th e pans togeth er,
there also may be alignment ta bs in
areas yo u ca n't reac h w ith yo ur fingers. Be sure the tabs are engaged as
yo u fit th e halves together, so the two
parts of the ho using for m an airtight
joint w hen you tur n the w ingnuts or
engage th e spring clips.
Be sure that both encl s of any ductwork are properly sea led to both the
air cl eaner body and the airflow meter
or throttle body, including hose cl a mps
or retaining clips. ~

HOW IT WORKS

Your Air Filter
The resin-impregnated ,
heat-cured "paper" element looks like a pleated
sheet, and most of the
dirt particles are stopped
at the outside surface. A
light coating of dirt actually improves the filtering
ability of the paper. But
soon the dirt builds up
and even starts filling
the bottoms of the pleats ,
restricting airflow. The
paper also has multiple
layers, and if you looked
at it under a microscope,
it would look like a forest
with an irregular crisscross of vines and limbsthe fiber strands of the " paper. "
It all looks random, but the premium-priced filter
"papers" are more consistent in the sizes of the pores
than it seems, and a quality material is a mathematically
predictable barrier to dirt particles. In actuality, the layers
of fibers form a maze and some of the dirt also is trapped
within the layers of the paper. The inrushing air produces

REPLACING

YOUR

AIR

FILTER

some static electricity,
which also causes some
smaller dirt particles to
adhere to the surfaces of
the paper fibers.
A point comes when
not enough voids remain
to pass the air needed to
supply your engine. The
result is inadequate oxygen to burn the fuel at
wide-open throttle. With
carbureted engines, this
used to mean rich running. Modern fuelinjected engines meter
the air admitted to the
intake and add appropriate fuel-making for a
clean-running engine that eventually won 't get out of its
own way. At least carbureted cars coughed and sputtered to let you know that you had a problem.
But with today's engines, a filter has to be really bad
to restrict acceleration . A bigger hazard is an overloaded
filter rupturing and dumping 20 miles of bad road into
your engine.

9

l

~ . EASY

\

Changing a Tire
la t tires a re never a fun
thing-but this o ne takes
the cake. It's late, of
course, and in the middle of a
frog-choking rain. You're stuck
in the a nkl e-deep mud on the
sho ulder of a deserted road.
How deserted? Our-of-cellphone-coverage deserted, or
yo u'd be sittin g in the cab of a
serv ice truck w hil e so mebod y
else gets drenched . That's how
deserted.
Yes, yo u could drive a lo ng
the should er 0 11 th e rim for a
few miles to civili zation, but
in sura nce wo n't cover the damage to you r expens ive a ll oy rim.
It's tim e to kn uck le d own an d
put o n th e spare.
A pressu re ca n of fl at-fix foam ca n
get you ho me if the problem is a simple
puncture, and that may be a viable
option, especially for smaller individuals or the elderly who would have a
tough time changing a tire . .lust reme mber two things: This stuff is a temporary
soluti on, and the fl a t will need to be
attended to by a tire technician at the
earliest opportunity. Be sure to wa rn the
technicia n that you've used this stuff.
The propel lant is fl ammable, and unless
he's wa rned, he sta nds the chance of
causing a nasty explosion. Aeroso l fl atfix, however, is no help if the problem is
a tire un seated from the wheel rim after
an encounter with a pothole.

F

I/ !

(Fig. 1) Be sure to check the air pressure in your spare tire periodically.
jack isn't rusted in to imm obility. C heck
the manual and find the ve hicl e's jacking poi nts. You ' ll proba bly need to lie
o n the grou nd to find them, but this
will be a lot more palatable now in
yo ur driveway than later on the sho ulder of some mud bog.

Grunting Helps

Furthermore, yo u' ll never be able to
cha nge a tire if yo u do n't have the
basics-a jack and a lug wrench (Fig.
2) . Go back into their hid y- ho le and
confirm their existence (Fig. 3) . W hile
yo u're there and you have enough light
to read the owner's manual , fi gure Ollt
how to un sh ip them and make sure the

The most co mm on difficulty in c ha nging a tire is lugs that are tighten ed far
too tightly. A cas ual rattle w ith a
mechani c's air wrench can deli ver a
tightening torgue that o nl y a pro
wres tl er could remove w ith the stock
lu g wrenc h. Wheel lugs need to be
ti ghtened to no more th a n t he manufacturer's recommended torgue to
ens ure the y won't loosen. C heck yo ur
(Fig. 2) loosening lug nuts calls for a
lot of upper-body strength. An inexpensive 4-way lug wrench can substantially
increase your leverage and break loose
overly tightened lugs.

Be Prepared
First of ail, remember to check the
pressure in your neglected spare tire
(Fig. 1) w henever yo u check tbe pressure in the other four, which yo u do
faithfully every mo nth or so, ri ght? A
flat spare is no help. An d if yo u' re like
most people w ho save a plugged or
nearly worn tire for the spare, it's likely
that the spare has a slow lea k, which
would leave yo u stranded.

10

MAINTENANCE BASICS

LUG WRENCH

(Fig. 3) Locate the jack and other tire tools and make
sure you know how to use them.

owner's manual, but the fi gure wi ll be
75 to 100 ft .-l b. of torq ue. Do the
math-that mea ns a 200-pound adult
should be a ble to tighten th e
lugs by placing all his weight on top
of the wrench only 6 in. away from
the fastener. A few drops of engine oil
or grease on the threads and the
lug chamfer (where the lug touches
th e whee l, not th e threa ds) wi ll
prevent ga lling and seizing.
When removing a wheel, first loosen
all of the lugs in a crisscross pattern a
half-turn or so. It may be necessary to
use the mechanic's favorite cheater bar
(Fig. 4)-a piece of water pipe
or thick wall pipe about 4 ft.
long- to add enough leverage
to break the lugs loose. Remove
them one at a time and lube
them if they squeak . Retighten
them in three stages, again in a
crisscross pattern.

Black And Round
Many carmakers, in a n
attempt to reduce vibration by
making sure the wheels are
more concentric with the hub,
use a protruding lip that mates
closely with the centerhole on
the rim. This works wel l for a

CHANGING A TIRE

(Fig. 4) A cheater bar helps loosen lugs. Never use it to tighten them.

coup le of years, but eventua lly corrosion from road grim e can make it
imposs ibl e to budge the w hee ls, even
after you've loosened all the lugs.
Correct this now, and you won't need
to try it in the field. Jack up the corner
of the car to take the load off the
wheel and kick the whee l, alternating
sides until it pops loose. No joy, and
now yo ur feet hurt? Be sure the lugs
are only a single turn frol11 tight,
lower the car and move it a foot forward and back, rapping the brakes
smartly to break the wheel loose. A
shot of penetrating oil may help in an

hour or two. Clean up the corrosion
with emery paper (Fig. 5) and coat al l
th e surfaces li ghtly with wheel bearing grease, Va se line or, best of all,
antiseize compound.
You' ll need a few things besides
the on-board tools for your emergency tire change. Pack a flash light
with good batteri es or, better yet, a
cigarette-lighter-powered trouble
li ght, an emergency triang le, a coup le
of road flares, some gloves and a poncho or ground cloth. Toss in three
pieces of scrap 2 x 4 as well, each
about a foot long, and a piece of thick
plywood 2 x 2 feet.

That Fateful Day
Wh en changing a tire the fir st,
and most important, thin g to
do is to get the vehicle to a
safe area, far enough from the
road to save you from becoming road pizza-particularly if
tbe flat is on the left side and
your back sid e wi ll be poking
out into traffic whi le you
work. Set your triangl e or
(Fig. 5) Remove corrosion from
the centering hole with emery
cloth or a wire brush.

11

jack, and there's probably
flares 100 ft. o r so upstream.
eno ugh to p ut a smidge n on the
Leave the ve hicle in Park and
lugs w ith your finger. Be sure to
set the hand brake. Block th e
get it on the mating chamfer as
whee l di agona lly opposite the
we ll as on the threads .
flat with two pieces of wood
Lower the vehicle and pull the
(Fig. 6) . Loosen all the lugs on
jack out. Now yo u can tighten
the flat a full turn. Take the
the lugs to their correct torque.
spare out of the trunk and put it
Check the owner's manual for
halfway under the car near the
the torgue specification. Measure
jack. In the unlikely event the
carefull y. If the lug is dry and
car fa ll s off the jack, it will onl y
unlubrica ted, it may take a lot
fall onto the spare-not your
more force to tighten the lugs.
foot or head-and will leave
,/'
The only accurate way to
you a fighting chance of raising
WHEEL CHOCKS
torgue the lugs is to use a
the car and continuing. If the
mechanic's torg ue wrench.
car falls to the gro und, yo u'll
T hese can be purchased for 20
(Fig. 6) Block the opposite corner of the car to keep
have no way to raise it.
bucks or so . If you have expenRaise the jack from its stowed it from rolling off the jack.
sive all oy wheels, yo u may want
position to nearly higb eno ugh
to bu y one and keep it in the trunk.
wrench, aga in in a crisscross pattern.
to contact the bottom of the car. If
Be sure you don't have anything
As yo u're putting away yo ur tools
you've got a different style of jack th an
(like a stone or mud) trapped
and jack, be sure yo u haven't left
the one pictured here (Fig. 7), check
your owner's manual for specifics.
between the rim and hu b, or the rim
them covered with mud or moisture,
which might ca use them to rust while
If the ground isn't firm, put the 2 x 2 w ill wobble. In fac t, if the mud COI11presses later, th e lugs co uld lose their
stored . If they're a mess, clean them
piece of pl ywood under the jack point,
and the jack o n top of th e wood. Be
torg ue and the whee l co uld fly off. If
and relubricate at your earli est opporyo u need to, remove th e whee l aga in
tunit y. Don't forget to pick up yo ur
sure everyt hing is level. Jack th e car
up until the fl at clears the ground by
in th e m orning to remove the debris,
safety tria ngle.
severa l inch es, beca use the spare isn't
corros ion a nd ru st fro m a ll th e matNext Morning
flat and will need more cl earance.
ing faces and between the w hee l an d
Remove the lug nuts, and put them
hub, a nd then li ghtly lube. This w ill
Take yo ur fl at to a competent tire
technician for repair ("Repa iring A
. inside the hubcap or in some other
have th e added benefi t of mak in g the
place where they won't get lost in the
w hee l easier to remove the next tim e.
Flat Tire," page 40 ). And don't let
dark, or accid enta ll y sca ttered into
him overtighten your lugs with hi s
Hint: There sho uld be so me grease to
the weeds by yo ur fee t.
be found o n the jackscrew of yo ur
fancy-dan air wrench. 9
Pull the flat off and put it
halfway under the car. Hang
the spare on the studs. No
studs? You've got lug bolts
(common on many Europea n
ca rs) and you'll need to juggle
the w heel w hil e yo u get the top
one started. The easy way is to
sit down on the ground facing
th e hub a nd ba lance th e spare
on yo ur legs w hile yo u start the
first lug bolt. If yo u begin with
the top bolt, the wheel will
hang gracefull y from it and yo u
can start the rest. Finger-tighten
a ll the lugs a nd then lightl y
ti ghten them w ith the lug
(Fig. 7) The correct jack point on
the frame of your vehicle may be
difficult to reach.

12

MAINTENANCE

BASICS

EASY

Replacing Your Tailpipe

rakelights flicker sudden ly in
fro nt of yo u, fo llowed rapidly
by the screeching of tires. Cars
before yo u swerve to the left and righ t
as you slow as safe ly and rapidl y as
practical. Despite yo ur best efforts,
th e so urce of the pandemon ium , what
appears to be half of a cement block,
di sappea rs directl y under yo ur front
bumper at a high speed. Thump. And
as it exits from yo ur rear bumper, yo u

B

REPLACING

YOUR TAILPIPE

follow it in your rearview mirror for a
few seconds. It has company. Your
muffler- or at least most of yo ur muffl er-ha s apparently developed a lasting relationship with the aforemen ti oned ce ment bl ock. They' re elop ing
at high speed toward the curb, in extricabl y intertwin ed.
The next thing you notice is the
sound of what seems to be a B-29
landing in the next lane as you press

back down on the gas. Actu all y, it's
your engine-minus its mufflerwaking LI p again as yo u try to negotiate through the traffic, back home to
sa fety, family and so mething ta ll and
co ld th at w ill make yo ur ha nds stop
shak in g.
To add insult to injury, yo u
replaced yo ur ex ha ust sys tem from
the cata lytic converter back only la st
spring. Inspection of the und erside

13

of yo ur car revea ls good , so lid p ipe
most of th e length of the ve hi cle,
ter min atin g in sha rd s of muffl er.
H ere's yo ur chance to rep lace a few
fe et of pipe and th e missin g muffler
yourse lf.

pipes it's connected to at both ends
have been crimped by cl a mps. How
do yo u remove the Sw iss-c heese pipe
witho ut ruining the o th er two ? By
using a power cutting whee l and a
very steady hand (Fig. 1). The preferred too l is an air-powered di e
grinder w ith a cutoff w heel, but a
hi gh-speed electric drill will work,
a lbeit more slowly.

oi l, so yo u can get th em o ut, pry the
fl a nge from its r usty partne r and
sec ure the new fl ange with a new gasket and fres h bo lts. Use antiseize
compound on everything to ease
removal the next time .
T he other type of co uplin g is made
up of a larger pipe slipped over a
small er one o r a small er pipe slipped
into a larger one, dependin g on wh ich

Now That You 're Home
Actua ll y, it may not be road debris
that removes yo ur muffler and
tailpipe. Rust never sleeps, and
cars in short-trip serv ice m ay
rust out the farth est, coolest
portion s of the exha ust system
in as little as 18 months.
Th e following scenario is
typical of vehicles that have
had part of th eir exha ust system repl aced at least once. T he
saga begin s with a section of
the origina l exhaust plumbing
behind the catalytic converter
rusting o ut and m aking a
ruckus. Beca use th e original
exhau st pipes are welded
together, however, a ll th e p ipes
from th e cat back need to be
(Fig. 2) Peel up the corners of the old pipe to slide in the new piece.
repla ced. T here's no practical
wa y to remove just the rotted
section because of all the
weld s.
If you had the wherewith a l,
you cou ld probably cut out just
th e rusted portion and have a
pipe custom-fitted. But th at
would be extremely labor' . .
intensive and not particularl y
econom ica l over the long ha ul.
Also, exhaus t work just isn't
don e that way. So , generally,
two or three aftermar ket pipes
and th e muffler a re clamped
togeth er behind the converter
(Fig. 3) After installing all the parts, adjust for fit and tighten the clamps.
to repa ir the exha ust.
T hen yo u dri ve aro und for
way the coupling is facin g. Both may
Sizing It Up
another yea r or two in peace and
be present in the same exha ust sysGet
the
back
of
the
car
up
on
jackquiet-unaware that the repl acement
tem.
The importa nt thing to rememw
ith
chocks
securing
the
front
stands,
pipes hangi ng under you tend to rust
ber
is
that yo u may need to save the
w
heels.
Be
sure
to
wear
safety
gogat different rates. Sometimes, th e midpipe,
so use a gentl e to uch w ith
inn
er
exha
ust
systems
tend
to
drop
gles,
as
dl e pipe of th e three you insta ll ed goes
the
cutting
wh ee l. If th e outer pipe
razo r-sharp flakes of ru st that a re
first . Other times, the muffl er at the
needs
to
be
saved, there's nothing you
seemingly attracted to your eyes .
end fa ll s off before the other two. Still
do
to
keep
fro m cutting it. But
can
Get under the ve hicl e to see what
other times , the fl anged pipe bolted to
why
yo
u're
going to use a cutthat's
kind of co uplings yo u' re dea ling
the cat is the first to go bad. In a ll
ting
wheel
instead
of an impact chi se l.
with. The fl anged type is easy. Just
cases, though, yo u want to replace
It
ma
kes
for
a
nea
ter,
smoother cut.
spray the rusty bolts with pen etrant
onl y th e bad pipe. Problem is, the

14

MAINTENANCE BASICS

o uter p ipe lik e a tin ca n. That w ill
g ive yo u enough play a t t he crim ped
area to w iggle the pipes apart.

Spread 'em

(Fig. 4) Smear muffler cement over the joint after you install the clamp.

Slice, Don't Dice
To begin, remove the bad pipe's
cla mps. Then, ma ke a lengthwi se
mark 'I to 2 in. lo ng where yo u want
to sli ce open th e outer pipe. Put on a
pa ir o f gogg les, get a good doubl eha nd ed grip on th e cutte r too l a ncl
sta rt it up . Slow ly ra ise the spin nin g
w hee l to the mark o n the pipe. With
gentle pressure, score the mark.

REPLACING Y OUR TAILPIPE

If yo u're saving the inn er pipe,
repeat this step until you're throug h
the outer p ipe. It's okay for the inner
pipe to get a li ttle score groove in itjust as long as you don't c ut it a ll the
way th ro ugh. [f yo u' re sav in g the o uter
p ipe, the second cut ca n take yo u a ll
the way throug h the inner pipe.
With th e cut made, use a screwdri ver or a c hi sel to pry ope n the

Fitting a new pipe over an o ld o ne is
no problem. Fitting a new pipe in to a n
o ld o ne sometimes is, because of the
crimp fro m t he o ld clamp. If you' re
hav ing trouble, use a n exhaust-pipe
expa nder to gai n so me ext ra cl ea ra nce .
Then, simpl y fit the pipes together as if
they were both new after smeari ng a
little muffler cement on the joi nt.
If yo u saved th e outer pipe, it
now has a 1- to 2- in . slice at th e
encl. Make sure to slide th e inn er
p ipe in past the end of the cut, so
there's no ho le between t he pi pes
(Fig. 2) . in sta ll a new muffle r cl a mp,
but do n 't tig hten it until the rest of
th e system is hung from th e ha ngers
a nd a ligned properly (Fig. 3) .
Once every thin g is back together
a nd c la mped dow n tight, a littl e
mu ff ler ceme nt strateg ica ll y a ppli ed
w ith yo ur thumb over th e c ut wi ll
take care of a ny tin y res idu a l gaps
(Fig. 4) . Lower yo ur car a nd enj oy
th e sil ence. t;

15

MODERATE

Repairing Power Antennas

(Fig. 1) Scratchy radio reception might be caused by poor ground or antenna
connections. Use an ohmmeter to chase high resistance pOints.

t's time to kick out some jams,
so you reach into the console for
your favorite MC5 CD. Popping
open the jewel box, yo u reac h for the
CD, only to find o ut that Juni or ha s
liberall y lubri cated it with peanut
butter and jell y. After making a mental note to give Junior a good ta lk ing-to, you dec id e to surf the a irwaves for some good oldtime rockand-roll. Punching the FM button,
yo u hope that at least one of the
radio presets ha s so me Bob Seger
tun es hiding behind it. But no,
th ere's nothing to be heard o n any
channe l except a great rushin g no ise,
not even so much as CONELRAD.
Time to come back to this mill ennium and find out what's wrong w ith
yo ur antenna.

I

16

Manual Or Power?
Fixed antennas have on ly a couple of
fai lure modes, and generally they
in vo lve mechanical damage to the
antenna mast or the ca ble. If part of
the mast is still there, yo u'll generall y
get so me sort of signa l. A poor connection between the antenna ba se a nd
the fe nd er also cou ld be a problem.
Unscrew the antenna mounting nut
and check for corrosion. A cleanup
w ith a w ire brush and reassembly
might re-estab lish a good gro und.
Powe r antenn as are more coy. If
they're too shy to come o ut of the
fender, yo u're li stening to static.

No-Show
The iss ue could be either electrica l or
purely mechanical. Go back to yo ur

(Fig. 2) If water that leaks down the
mast can't escape, the mechanism
may freeze up.

antenna and tr y to pull the mast o ut
with your fin gers. If it moves out
readily, pull it out all the way, and
then cycl e the radio power w ith the
key on. If the mast moves even the
slightest amo unt, or yo u can hear the
motor running at a ll, the prob lem is
mechanical.
If the motor seems deceased,
go back to basics-check the fuse.
Determining which fuse protects the
antenna motor may require so me
detective work . It may be the radio
fuse, or it may be a separate fuse, perhaps shared with the rear-window
defroster grid or a trunk-mo unted CD
changer. (Finding something else that
doesn't work often is a good clue.)
Fuse is okay? Check the antenna's
mounting, as described previous ly, for

MAINTENANCE BASICS

(Fig. 3) A sticky or damaged antenna
mast can often be replaced without
accessing or disassembling the mechanism. As we show here, this can be
done without removing the interior trim.

assembly sho uld have o ne hot w ire
o n, a nd a di ffere nt w ire hot when th e
key or rad io is off. Good huntin g.

Stubborn
a good gro und pathway, a lth o ug h
there ma y be a separate gro und w ire
to a spec ific chassis gro und point. You
may want to use a n o hmm eter (Fig. 1)
to hunt for resistance. Inci denta ll y, if
yo u tr y to meas ure th e res ista nce of
th e a ntenn a cable's RF lea d between
the mas t a nd the radio connector, it
ma y check out as infinite. Some
a ntenn a assemb lies use a capac itor in
series w ith the RF lead , some don 't.
T he ground shell of the a nten na cab le
shou ld have a low resistance to chassis gro und , normally 5 o hm s or less .
You' ll need to find a schema ti c of
the a ntenna w iring to tro ubles hoot
a ny deeper. But with the radio and
key on, the harn ess to the antenna

REPAIRING

POWER

ANTENNAS

Does the antenna motor run briefl y
but not ac tu ally move the mast up
a nd down? Or does it move a few
inches a nd th en grind to a ha lt? One
prob lem we've seen is a kinked o r
pinched drain tube. (Fig. 2) The mechanism ca n fill with water, w hich then
freezes solid in cold weather, or corrodes the works and causes a jam.
C heck the tube, espec ia ll y if yo u can
pull th e mast o ut manually a nd it's
wet. If the tube is compro mi sed an d
the works are full of water, you may
need to disassemble the thing, dry it
o ut, and put it back together with
fresh lubrica nt.
Ca n yo u help the mast along in
and out? If so, the sliding sections

of th e mas t may be corroded or bent.
Careful bending by ha nd may resto re
mo ve ment, a nd po li shing with 600-grit
sandpaper or rubbing compound ca n
smoo th th e action. At the ve ry least,
run the mast compl etely out a nd cl ea n
it th oro ug hl y with a soft cloth, re lu bri cating w ith a spa rse a mo unt of silicone grease or pas te wax.

What's That Funny Noise?
Modern power a ntennas use a simpl e,
fl exibl e rac k-a nd-pinion mecha ni sm.
It's pretty reli able, but a buse and the
ravages of time a nd weather ca n litera ll y st rip the gears . So if yo u hear
noises that sound li ke interru pted gear
meshing, there's probably some section
of the rack or pinion th a t's in need of
denta l work. It's poss ible to fix thi s
w itho ut replacing the a ntenna asse mbly o utright (Fig. 3) . (You m ay not even
have to access the mecha nism .)
~

17

FERRULE

(Fig. 4) Remove the outer nut and
collar as a first step to removing or
replacing the mast.

Visit yo ur dea lership 's parts department. GM, for one, offers a repair kit
fo r p ower a ntennas . T hi s consists of a
new mast a nd rac k asse mb ly, rea d y to
in sta ll. You may need to order it, as
the two dea lers we tri ed didn 't have it
in stock . Th ere are afte rmarket
antenna pa rts to be ha d, but finding
th e ri ght pa rt is going to be di ffi cult
unl ess yo u have better lu ck than we
did interroga ting the staff behin d the
pa rts co unter a t the loca l ware ho use
di stributor.
H ere's how the system works: Th e
limi t switc hes that stop th e motor at
bo th end s of th e antenna ma st's trave l
a re built in to the mech a nism , a nd yo u
ca n consider them un se rviceab le. T he
limit switches rely on th e a ntenn a bo ttoming o ut o r topp ing out to ro ta te a
sw itch drum , a t which po in t th e c urrent to the motor turn s off.
At the top of the antenna mechanism
is a large nut that holds the who le wo rks
onto the fender. Remove this nut. T his
isn't as easy as it sounds if it doesn't have
flats that yo u ca n turn with a wrench.
Yo u may need to use a spanner w ith
pins- a ltho ugh a pair of snap rin g pliers
may work if the nut isn't w icked ly tight.
At the potentia l expense of the chro me
fini sh, yo u may need to fa ll back on the
mechanic's friend, locking pliers. Under
the nut and perhaps a plastic spacer or
two there wi ll be a ferru le (Fig. 4) , which

18

is the stepped sleeve that the mast actua ll y bumps into at the end of its travel
upward. Pul l o ut thi s ferru le. Now have
someone else turn on the radio. The
mast should elevate itself comp letely out
and flop over, so you have to be there to
catch it. Carefull y notice which way the
teeth of the rack point as the mast clears
the fender. Note the state of the teeth.
M issing teeth proba bl y mea n yo u
sho uld disassemble the ho using and
clea r a ll the bits o ut, but teeth that are
simply worn shou ld be okay.
The new mast's rack has been
cu rled up lik e a p ig's ta il in th e package, and it will be difficu lt getting it to
mes h with th e gea rs. With yo ur fin gers or pli ers, bend th e bottom 2 or 3
in. backward to remo ve the c url. The
end sho uld be stra ight now. After
ma king sure tha t the ra di o is turned
o ff, take a look at th e last too th-you
may need to remove a sm a ll a mount
o f castin g fl as h. A pocketknife does
th a t job we ll.
Tak e th e new ma st, wit h th e teeth
of its rack a ppropri a te ly oriented,
a nd in se rt it in to th e ho le unti l it bottoms . Rota te the mast a littl e to the
left and ri g ht to get th e teeth to mesh
w ith the pinion gea r (Fig. 5) . H ave
yo ur helper turn th e rad io o n a nd off
w hil e yo u pu sh th e new m as t firm ly
down. Thi s wil l ca use th e limit switch
to cycl e in sid e th e mecha ni sm. Now
have yo ur help er turn the radi o o n,
a nd if a ll is we ll , the mas t w ill suck
itse lf very nea tly in unti l it bottoms
o ut. All yo u need to do now is reinsta ll the ferru le, space rs a nd nut.
Ligh tl y lu be the mast sectio ns w ith
sili cone grease o r pas te wax.

runnin g aga in. The sw itch co nsists
of a pl as tic drum w ith wiper fin gers
a nd electri ca l traces, so it's vu lnera bl e
to moi sture a nd dri ed-out lu bri ca nt. If
yo u ca n't fi x it, or th e motor itse lf is
toasted, yo u'll n eed to replace t he
w ho le shootin' ma tch. An afterma rket
a ntenn a w ill set yo u back about $60
to $75 at th e loca l a uto p arts store, or
mo re than a hundred a t th e dea lermaybe mo re for a lu x ury impo rt. The
OEM parts w ill , of course, dro p in.
Aftermark et pi eces m ay require a
certain a m o unt of a daptation to
mount properly, a nd perhaps even
some crea ti ve w irin g to make th em
wo rk prope rl y. Don 't forget to chec k
for used pa rts a t the loca l scrapyard
o r auto recycl er. t)

NEW MAST

Outer Limits
If the limit switch mechanism stops
work ing, yo u m ay be a bl e to d isasse mble it, cl ea n up a n y fore ign matter
o r corrosion, a nd get it
(Fig. 5) It may take
a little fumbling to
get the rack to
mesh with the drive
pinion, but when it
does the mast will
run completely
home by itself.

J
MAINTENANCE BASICS

,- 0

EASY

l~~PlaCing Your Spark Plugs
es pite the heavy traffi c-peri ods of slow-go
inte rsp ersed w ith lo nger
per io ds of no-go-thin gs a re
okay. Yo u've gOt tha t new
Ya nni disc in th e playe r a nd
yo ur java is still piping ho t.
H o w eve r, as yo ur dri ve wea rs
on , the CD starts skipping and
th e co ffee in yo ur cup sta rts
spilling ove r th e to p. Suddenl y
yo u rea li ze th a t yo ur engin e is
no lo nger idlin g w ith its a cc ustom ed silk y sm oothn ess. In
fac t, it's getting as lumpy as
cold oatmeal. Th e engin e's
deve loped a ba d misfire.
As yo u sit a nd jiggle a lo ng in
th e ro ugh-runnin g car, yo u fi gure th a t it ca n't be the spa rk
plugs. After a ll , w ith today's
unl ea ded gaso line th ey can last
twice as long as they used to.
And th e engine's high-o utput
electronic igniti o n system produces eno ugh vo ltage to fir e
even a wo rn plug.
Well , think aga in.

D

Fair is foul
Altho ug h plu gs w o n 't lea d- foul
w ith today's unl ea ded gasolin e, they can o il-foul , ca rb o n -fo ul
o r even be fo ul ed by so m e fue l a dd iti ves. So if yo u 've go t a mi sfire,
th e re's a fa ir c ha nce a plu g is th e
ca use . In fac t, it's mo re like ly a plu g
th a n th e fue l inj ec tor. So, back
ho me, it 's tim e to take th e plugs o ut.
Loo k fo r oil y- bl ac k or soo t y ca rbonbl ack dep os its. The fo rm e r us ua ll y
are fro m defec tive in ta ke va lve stem
sea ls, th e la tter fr o m a n ove rl y ri c h
fu e l mi x ture, o r a lazy o r d e fec ti ve
oxyge n (0 2 ) se nso r. T he oxygen se nso r is wh a t s ig na ls th e co mpute r to
a dju st th e fu e l mix ture.
It ca n be tough to hear a misfire,
which is o ne reason w hy emissi o ns-

REPLACING YOUR

control sta nd a rd s require the engin e
computer's o n-boa rd di agnostics
(O BD ) to log tro ubl e codes fo r each o f
th e cy linders. H o weve r, th e first ca rs
equipped with that setu p (ca ll ed O BD
1I) we ren't produ ced until 1994 , a nd
most cars didn 't have it until 1996 .
Even w ith a n ea rlier model , yo u
sho uld c heck fo r tro ubl e co d es indi ca tin g a pro bl e m with th e eng ine,
pa rti c ul a rl y th ose in vo lvin g th e oxyge n se nsor. But if eng in e pe rfo rma nce is d o wn a nd yo u ' re no t seeing tro ubl e co des, a nd th e plu gs
have gon e a co upl e o f yea r s o r
a bo ut 30,00 0 miles, it's wo rth
pullin g the m fo r a loo k. But no t so

fas t-thi s ma y not be as ea sy as in
yo ur las t ca r.
F irst, it may be ha rd e r to di sco n nec t th e plu g wires. If th ey' re
recesse d , yo u ca n ' t ju st pull o n th e
w ire. Wo rse, m ost of th e s impl e
spa rk plu g pull er s w e've tri ed wo n ' t
w ork o n a stuck boot. You need plie rs th a t grip th e end o f th e boo t
a nd g ive yo u so me thin g so lid to
ho ld. Th ese pull e rs cos t $20 o r so .
In a n y case, t w istin g th e boo t to
brea k th e heat sea l ofte n is necessa r y, eve n w ith p li er s. Neve r tr y to
p ull o n the plu g wire itself, o r
yo u'll prob a bl y cau se a se parati o n
in th e res ista nce wire.

SPARK PLUGS

19

A second thing to watch for is
whether yo ur spa rk -p lug socket really
fits. To meet th e lates t standard of th e
Society of Automo ti ve Engineers,
many new plugs are about Ys-in.
longer than yo u're pro ba bl y used to.
An o lder, margina l soc ket may not fit
the hex properl y and co uld slip off
and break the p lug. It also helps to
use a socket w ith a rubber in sert to
sec urely ho ld the plug.

Finally, the elbow grease
Start wi th a warm engine. Clean the
plug ho le recesses with compressed
air, crack a ll th e p lugs loose one-quarter turn, and let the engine cool.
Removing plugs from a ho t cylind er
hea d ca n damage the threa ds.
Once yo u have the plugs out,
check them ca refully before yo u
dec id e they've got a lo t of li fe left.
Use a ma gnifying glass and fee ler
ga uge to be sure . If the ga p is worn
.005 in. over the specs, an d yo u can
see ro undin g off of th e ce nter electro de and wear o n th e sid e electrode,
in sta ll new p lu gs. Forget trying to
fil e the plugs .
If yo u're reinstalling the old
p Iugs, smear a film of antiseize on
the threa d s near th e tip. New p lu gs
have a coat in g th at w ill lu bricate
th e threa d s o n th e way in a nd preve nt the p lu g from se izin g on their
next removal, but it 's o nl y good for
one stab.
If a ny sp ark plu gs are dry-soot
black, that's from carbon-a richfuel mixture problem. If there's a
trouble code indi ca ting the oxygen
se ns o r is incorrectl y sign a li ng lea n,
the sensor co uld be responsible. If it's
correc tl y indicating a rich mixture,
then yo u have to look for a cause,
such as leaking fuel inj ectors or
engi ne misfire, perha ps ca used by
defecti ve plug wires. It wou ld seem
th at mi sfire wo uld thro w a lot of raw
gas into th e exha ust, whic h it does.
But it also th rows in a lo t of oxygen,
and th at's w hat th e sensor sees, and
in thi s case it just tells the comp uter
to add more fuel.
No t sure or no code? Then check
th e oxygen sensor, w hi ch resemb les a

HOW IT WORKS

The Right Plug
The correct plug for your
engine is, of course, the
exact part number that
the manufacturer
installed at the factory.
When it's time to retire
them, you'll be forced to
choose from several
manufacturers' offerings,
and they're all pretty
much alike, right? Wrong.
There are subtle differences in a plug's ability to dissipate heat that belie what would otherwise
be an exact physical match. A "hot" plug has a long path through the
ceramic to the (relatively) cool cylinder head. A "cold" plug has a shorter
heat-conduction path and tends to run cooler.
Plug manufacturers cross-reference their product lines to other manufacturers' lines, and you should be able to find a plug to fit almost anything
in the cross-reference chart. More important than heat range are things
like thread diameter and length, and the type of tip .
Installing the wrong plug can ruin your engine instantly if the plug is
too long and whacks the top of the piston, especially in today's aluminum heads.
Too short a plug not only won't fire, carbon will quickly fill the threads on
the cylinder's head, preventing you from installing the correct plug.

spar k p lu g threa ded into the ex hau st
manifold . If there's an O 2 trouble
cod e a nd no apparent ot her ca use,
yo u cou ld just rep lace the sensor. O r,
before yo u in vest in a new one, test
the se nsor yo u' ve got. You ca n do
this using one of the inexpensive
testers made for Saturday mechanics.
With a warmed-up engine (necessar y
to get the O 2 se nsor work ing) a nd
the throttl e cracked open (so th e
engine is running at abo ut 2000
rpm), the tes ter's indicator lights t ypica lly wi II fla sh o n and off (or w ill
both glow stead il y) if the O 2 sensor
is working properly.
If yo u don't get the lights, or as an
extra check, let the engin e coo l.
Remove th e sensor w ith a tight-fitting
wrench and bench-test it. The typ ica l
sensor ha s a closed but slotted end
and is a heat battery of sorts. If you
envelop the senso r end w ith the flame
of a propane torch (so it gets hot but
not cherry red ), it should produce

over OAv with a high-impedance digital vo ltmeter hooked up, or turn on
th e tes ter li ghts. If the sensor is good,
th e vo ltage should drop or the lights
go o ut w ithin 3 second s after yo u pull
away th e fl ame.
Occasiona ll y a vehicle has a different
type of sensor, and in some designs it
has an open tip. This is a varying-resistance device that doesn't respond to
these vo ltage-generating tests, so yo u'll
have to rely on the on- board diagnostic
system fo r openers, and a shop manual
checko ut procedure to find out if it's
bad. T hi s type (widely used on new
cars) also was used on 1987-90 Jeeps,
an occasional Toyota in the late 1980s
and a lot of N issa ns. These days yo u
shou ld ha ve access to factory service
information (or a good afterma rket
eq ui va lent) for yo ur car, so refer to it.
Whether yo u install a new sensor
or refit the one you've got, coat the
th reads of the 0 , sensor wi th anti seize compound.- ~

MAINTENANCE

20

BASICS

EASY

Replacing Spark Plug Wires
(Fig. 1) Dampen the wires with a
spray bottle and clear water, and look
for arcs with a grounded, insulated
screwdriver.

(Fig. 2) Inexpensive
boot pliers allow
you to remove
stuck plug wires
without damage.

efore easing o ut of the fas tfoo d 's parking lot, you gra b a
sip of the hot coffee you
picked up at the drive-thru. You take
yo ur time as you p lace the cup in its
ho lder in the center co nso le. No
hurr y. Th e a pproaching traffic may be
mo ving fas t, bu t it's far enough away
for you to accelerate up to cruising
speed. Good thing, beca use at a bo ut
half-throttl e you fee l the engine mi s-

B

REPLACING

SPARK

PLUG

WIRES

fire. The cl osing traffic ha s time to
back off and let yo u sputter up to
road sp eed . But n ow yo ur engine
sputters like a H arl ey idling at the
curb, eve n at norma l tra ffic speeds.
And there's coffee a ll over the co nso le
fro m the vibrati on.

What's Up?
A brief underhood inspection co nfirms that all th e vacuum hoses are o n

and that none of them have been
burn ed open by lea ning against th e
exhaust manifold . Yo u've touched
every sensor connection to see if
it's o n tight, you 've even checked for
troubl e codes .
H owever, not everything ca ll s fo r
high-tech di agnosti cs a nd the latest
scan tester. Engin e mi sfire often is
ca used by lea king spa rk plug wires, so
visu al inspection could re veal what's
wrong . Th e jackets may be damaged
fr om the outside by a brasion ca used
by engine vibra ti on (p articul arl y at
the plug-end boots), a hot engin e
compartment, spill ed fluid s or battery
acid , multiple disco nnectio ns and
reconnections for other service, o r
even a fa mil y of nesting rodents.
Run the engine in near darkness,
and then look and listen. If you see
littl e electrical arcs, or hear a snapcrac k, th ere is hi gh-vo ltage electrica l
leakage. Of co urse, running the
engine at idl e doesn 't exercise the
igniti on system ve ry hard , so yo u ca n
add so mething to the test by spray in g
the plug wire ends with clean wa ter
fro m a ho usehold spray bottle.
Another test: With a jumper w ire,
ground the metal shank of a screwdri ver that has a well -in sul ated handl e.
Then, run the tip of the screwdriver
along th e length of each wire and a ll
around at the coil and plug boots. Thi s
w ill often produce an arc from the wire
to th e screwdriver (Fig. 1) .
Now look at the wi res und er good
lighting. If they are da maged by a brasion, o il-soa ked, cut, burn ed fr om
contac t with the exha ust, or have a
dried-o ut look with hea t cracks, it
definitel y shouldn't be a surpri se if
yo u see arcs in the dark under so me
conditi ons. H owever, if they loo k bad

21

but th ere a re no arcs, do a res ista nce chec k.
A conve nti o na l plug w ire has
a res ista nce of 10,000 to 15,000
o hms per foot of length-if it's
meas ura bly high er, t he w ire
probab ly is bad. An a bso lutely
failed w ire w ill have a ha irline
brea k so mew here, a nd t he res ista nce wi ll be infinity.

affect th e operatio n of underhood e lectro nics by not co nta in ing radio waves.
T he ac tual method of removing the o ld wire is not a lways
" ju st pull it off." Pulling o n th e
w ire itse lf is sure to cause an
intern a l separa tion (see p. 19).
Of course, if yo u' re replacin g a
ba d wire , it may no t ma tter, but
if anyone of th e o ld w ires is
Out With The Old,
st ill good, it's bes t to kee p it as
In With The New
a spare .
Once yo u've found a bad w ire,
Grasp the plug wire by the
the so luti on should be simpl e:
boot at the plug end. If it's in a
(Fig. 3) Some wires are secured inside the cap by
Rep lace the plug w ires .
recess or is difficu lt ro access for
spring clips. Use needle-nose pliers here.
First, yo u have to decide
some other reason, use a spa rk
whether yo u want to bu y from a
plug wire too l. There are specia l
car dea ler a t Iist price o r get
A word of ca uti o n : You may no t
pliers of a ll sorts designed ro reach in
a qua lity aftermark et bra nd, if you have
wa nt " hig h- perfo rmance" wires, even
a nd grasp the boot (Fig. 2) . They' re no t
that cho ice. Prices for 198 0s models
if th ey fit yo ur ca r (and they may be
expensive, and having them could prove
ma y be under $35 for a popular make
cheaper th a n a conventional type) .
useful if you ever have ro discOlUlect
at the parts srore. For a late-model V8 ,
Some high-performa nce w ires are not
w ires for other underhood service. Twist
be prepa red to pay the dealer up to
th e resistance type, and a lth o ugh they
the boot if necessary ro break the heat
$200 o r mo re, even for a popul ar car.
m ay do well o n racing cars, they can
sea l to the plug, then pull . As yo u do this

HOW IT WORKS

Spark Plug Wires
The spark plug wire has a seemingly
simple job: Carry the high-voltage
electricity produced by the ignition
coil to the terminal of the spark
plug. Once at the plug, the electricity travels to the other end of the
plug, and jumps a gap between electrodes to produce the "spark"
that ignites the fuel mixture.
Because high-voltage electricity looks for an easier
path to jump across than a
pair of electrodes in a spark
plug, containing the electricity within the wire takes a
thick jacket of insulation, and
some wires have an outer
jacket to resist cuts, high
underhood temperatures , etc.
If that outer jacket is damaged, the electricity may leak
out to follow the easier path.
In addition, high-voltage electricity produces radio waves,

with all types of on-car electronic
devices, from sensors and computers to radios and other entertainment systems. So, a simple length
of solid wire can create problems.
The electrical conductor typically
has a carbon-impregnated core of a

THICK RUBBER
INNER
INSULATOR

CONDUCTOR IS CARBONIMPREGNATED NYLON
STRING [AVOIDS RADIO

suitable fiber, and everything from
nylon to Kevlar has been used by
different makers. That conductor
(often covered by a second layer of
a nonconductive material such as
synthetic rubber) has enough electrical resistance to suppress radio
interference without unduly
weakening the spark. Some
premium wires may have copper or stainless steel wire
wound around the carbon
core to reduce resistance. In
some special applications in
which minimum resistance is
needed for engine performance, a solid metal wire has
been used as a conductor,
but over the inner layer of
insulation is a layer of wound
wire as a shield. On other
types of wires, the outer
f h'
h
jacket 0 t e wire may ave a
metallic shield to prevent

D

L-_W
_h_i_c_h_c_a_n_c_a_u_s_e__in_t_e_rf_e_r_e_n_c _
e ________________A
_N
_D
__TV
__I_N_
TE_R
_F
_E
_R
_E_N
_C
_E
_l____________i_n_te_r_f_e_re_n_c_e_._______________

22

MAINTENANCE

BASICS

(Fig. 4) Replace plug
wires one at a t ime to
maintain the exact same
routing as original. Use
silicone grease on the
boots to allow easy
removal in the future.

take note if you fee l some
looseness at the connection
(it may have been ca used by
engine vib ration).
The plug w ire usua ll y
is more accessibl e at the
co il end , but it m ay not be
a sim ple p ush-on. Si nce
th e ea rl y 1980s, C h rys ler
plug w ires o n engi nes
w ith distr ibutors have
been held in the cap by
spring c lips. Co mpress t he
tan gs of the clip with pliers a nd pu sh out to di sengage t he wire (Fig. 3) .
Some Japanese makes
have t h read-in" boots."
Foll ow th e r o uting of a
spa rk plug wire as if it were th e road
to success, beca use when it com es to
engin e opera tion, it really is. Every
ma nufacturer includes li tt le plastic
guides, and altho ugh they may cost
pe nni es to make a nd in sta ll , they're
used to locate each wire so it doesn't
cause crossfire (a tra nsfer of high-vo ltage electricity from o ne cy linder's w ire
to th e o ne that's next in the fir ing
o rd er) (Fig. 4) . If yo u see o ne wire
crossing over or under a no ther a t
nea rl y r ight ang les, t ha t's a n example
of the ro uting strategy used to avoid
crossfi re.
Of co urse, o n so me engin es w ith
co il -on-p lug igniti o n (COP), th ere is
no w ire and the boot is o ut of
sig h t, out of mind. Al th ough
t hi s type is immun e to hungry
rodents, a boot m ay suffer interna l d a m age from hi g h-vo ltage
e lectric ity o r crack in g from
engi ne hea t. It's eve n possibl e for spill ed o il to fl ow
und e r th e cover a nd ge t
d ow n o nto the boots o n
some cars, so ha ve a rag ha nd y
w hen yo u 're ad dlI1 g eng lll e Oil. It's

th e engi ne running, so you've got to
remove th e igniti o n cover a nd li ft t he
COP modules to make a physical
in specti on. T here are so me " hyb rid "
des igns, w ith o ne coi l o n o ne plug t o
serve two cy linders (Fig. 5) . The co il
directly feeds a plug in a boot und ernea th , a nd th ere's a plug wire
(rep lacea bl e) to a seco nd p lug.
T he COP boots a lo ne are usua ll y
(Fig. 5) Many newer
cars have individual
coils mounted on the
plugs. Short wires
connect opposite-firing
cylinders.

und er $25 a set, a nd are stri ct ly a
d ea ler part. Ju st pu ll the co ille lectronics modu le off the plug a nd t hen pull
the boot off th e mod ul e. If th e boot is
integra l to the electro ni cs th e price
co uld be $ 100 each.
There's no mainte na nce you ca n
perform to extend the li fe of plug
w ires. However, before yo u insta ll th e
boot o n th e p lug, coa t th e in side wit h
boot re lease lube (a silicone grease) to make it
eas ier to re move next
time. And w henever
yo u wo rk und er t he
hood , avo id nic kin g th e
w ires, sp illin g so lve nt
on them, or mishandlin g if you have to set
them as ide w hil e yo u
work o n something else.
And if yo u see a w ire
da ngling ve ry close to
t he ex ha ust ma ni fo ld,
reposit io n it in its
g uid e to ga in so me
clearance. A penny of
prevention can be worth
a co upl e of hundred

L-_i_nl_p_[_'a_c_ti_c_a_l _to__c_h_e_c _k _t_h_e_se__b_o_o_ts__w_i_t1_1._______________________________________________d_o_I_la_I_
~s_0_f_c__ure.

REPLACING

SPARK

PLUG WIRES

~~
23

EAS"i

Maintaining Your Tires

(Fig. 1) Always check your tires cold.
Driving even a few miles will heat them
up and change the internal pressure,
possibly masking underinflation.

ably when the tires are overnight cold,
or when it has been at \east 6 hours
y kind of tire failur e- even a
since the vehicle was driven (Fig. 1) .
sirnp\e flat- is a h uge hassle.
D on't try to "eyeba\l" a tire for norload, not what the tires are physiBut this can be avoided with
mal inflation. You can't te\l the differcally capable of withstanding.
careful tire maintenance. It the recent
ence between a properly inflated tire
Although tire pressure specificatire reca\ls and reports ot tread sepaand one that'S even 10 psi under.
usually peak at 32 to 36 psi, buy
tions
ration have alerted yoU to the imporSome tires always look underinflated.
a tire pressure gauge that reads to at
tance of regular tire inspection and
Some have stiff sidewalls and always
ust
\east 60 psi. That'S a typical pressure
care, you're ready to go beyond i
a
look nOrlllally inflated.
specificati on tor a compact spare. 1£
quick look to make sure the tires
R ead the tire specification label,
the vehicle manufacturer specifies a
aren't flat. Most fa ilures are caused
which usually is on the driver's tront
pressure range, such as a minimum
by underinflation, overloading your
doori a
or the matching surface on
and a maxin"\llm, alwayS use the maxmb
vehicle, or damage trom debris, curbs
the pillar (Fig. 2) . T hese pressure
imum. The higher the pressure, the
and potholes. These are things yOU
specs usually are lower than the
greater the load-carrying capacity of
maximum pressure allowed on the
can check yourself.
the tire, the more stable the vehicle's
tire's sidewall, but they' re based on
pref\\ght inspection
each particular vehicle and its rated
At least once a month, check your ertire
pressures- in your driveway, pref -

A

24

Inspecting Tires

to a sharp edge at one or both sidesor mu ch grea ter o n o ne sid e is a sign
of mi sa li gnm ent.
sha rp rock, of course yo u' re going to
If yo u see cuplike wear in th e
look as soon as possib le for damage.
But remember, even if th e exteri o r
trea ds, typ icall y along one side, th e
possibl e ca uses are wheels that are o ut
looks fine, the tire may be damaged
inside. Although it may not slow-lea k, of balance, worn -out shocks or struts,
a nd loose suspen sion components.
it co uld fai l suddenl y. You'd be wise
The class ic sign o f unbal a nced w hee ls
to get th e car to a tire shop so th e tire
is high-speed (50 mph and up) vibraca n be demou nted a nd given an interti on, and it usuall y surfaces before th e
nal inspection. Th e few doll a rs is a
cuplik e wear becomes noti cea bl e. Susgrea t in vestment in peace of mind,
pensio n problem s usuall y p roduce
and if there is interna l da mage, fo rget
shake at lower speeds.
abo ut a pa tch. Inves t in new rubber.
Look for any cuts on the
surface of the tire that
expose th e steel belt o r fa bWEAR
ric cord. This is gro und s for
INDICATOR
BAR
immedi ate replacement.
Tires w ith un eve nl y
worn trea ds sh ould be
replaced , unl ess the problem is ca ught ea rl y and
there 's pl enty of trea d
dep th left . In tha t case,
th ey co uld provid e a moderate amou nt of life o n the
rea r wheels, particu la rl y
on a fro nt-dri ve car. Ho w(Fig.3) Check the tread for cuts, foreign objects
ever, if yo u have an a lland abnormal wear. The wear bars will indicate
w heel dri ve that yo u pu sh
when the tire is worn out.
pretty hard, invest in an
enti re set of new tires .
Wheel a lignment a lso pl ays an
important ro le in tire perfor ma nce. If
Wheel Balancing
the w hee ls are mi sa ligned , they don't
Most shops have off-ca r electronic
ro ll tru e down the road. T he side sli pbalancers that allow the wh ee ls to be
page produces friction, which raises
rotated to any position wi th out affecttire temperatures and not only
ing their balance. The disad va ntage is,
increases tread wear but ca uses the
if there's any unbalance in the w heel
wear to be uneven .
So in spect the tire treads. As yo u
hub, it won't be corrected. If thi s doesn't cure the vibratio n, it's wort h find do, pry o ut pebb les from the grooves .
T hey reduce traction and can damage
ing a shop with on-ca r equipment
th e tread a rea .
before yo u try something else . In add iThe tread s sho uld be deepest at
ti on, make sure the shop has weights
designed for your wheels. It ta kes at
midpo int-at least Ys in. thick . That's
)\6 in . above the tread bars th at are the
least a half-dozen differentl y shaped
official "replace them " indi cators
weights to fit properly on th e rims of
(Fig. 3) . H oweve r, yo u need tread
all the p opular w heels . There are severa l so-ca ll ed "u ni versa l" we ights, but
a bove th ose bars o r the tire wi ll do a
poor job of shedding any water a nd
th ey may not fit yo ur rim , a nd co uld
slu sh it runs into o n the road. The
pop off or ca use rim dama ge.
wear pa ttern sho uld be rela tive ly even
If the w heels a re balanced and yo u
at each side, a lth ough it might be
have wheel shake at medium speeds
somew hat grea ter in the middle.
on up, or the tires ha ve cup wear,
Trea d wear th at is "fea th ered"-worn check the sh ock s and struts.

If yo u hi t a road hazard such as a

(Fig. 2) Appropriate tire pressures are
listed on a sticker on the doorframe or
the matching door pillar.

hand ling w ill be, and the coo ler the
tire will ru n at speed. All tires leak air
press ure over tim e. Th e closer the
tires are to the recom mend ed maximum press ure, the greater th e safety
ma rgin for a ll op eratin g parameters.
A no rm al tire lea ks about .5 to 1 psi
per month.
In additi o n, as ambient temperatures drop wit h th e changes of sea so ns, so do the ti res' air pressureone psi per 10°F. It might seem th at
th e temperature-related drop is
marched by lower operating temperatures of the tires in cold weather. But
the key to tire safety is adequate pressure to carry yo ur ve hicle's load .
Although hi gher rire pressures
sti ffe n th e ride so mew hat, it's a small
price to pa y for th e ex tra safety and
the a bility of the ve hi cle to accommodate greater loa ds. Ma inta ining
proper tire press ure a lso improves
fuel economy, altho ugh not by much.
Ca ution : Overinfl atio n increases
center tread wea r.
Do n't forget th e sp are. And note
o ur ea rli er wa rning abo ut the higher
spec ified pressure for a compact
spare. If yo ur spare is carri ed in the
underbody, as it is on man y minivans,
yo u' ll need to craw l underneath with
a pressure ga uge and air hose.

MAINTAINING YOUR TIRES

25

HOW IT WORKS

Reading A Passenger Tire Sidewall
RADIAL

A "P" or "LT" stands for passenger car or light truck tire.
The 3-digit number (215 on
this diagram) is the tire
cross-section width in millimeters. The 2-digit number
that follows (65) is the
aspect ratio-the height of
the sidewall relative to the
cross-section. A lower number indicates a wide tread
area relative to the sidewall-today's sporty look.
The letter "R" means radial
tire construction. The next 2digit number (15) is the wheel
rim diameter in inches. A 2-

~

.• ':..

digit number following the
size information is a load-versus-pressure rating. A letter
that follows that 2-digit rating
is a speed rating. Example:
"S" is for a tire rated for
speeds up to 112 mph. You'll
also find maximum pressure
(in psi and kilopascals), and
maximum load (in kilograms
and pounds). In addition,
there are numerical or letter
grades for relative tread life,
traction and temperature
(UTQG). The layout of the
information may vary accordingto make.

LOAD INDEX
AND SPEED
RATING
DOT
SAFETY
CODE

UTQG RATINGS

.

(Fig. 4) Minor scraping on the rim's lip is okay, but a
bent bead surface may cause a leak or vibration.

Sidewall Check
Us ing a tire and w heel cleaning
product wi ll give yo u a cl ear loo k
at both th e tires and whee ls. Yo u
shou ld be ab le to fin d crac ks in th e
whee l, damage beyo nd surface
nicks to th e tire sid ewa ll s, and
dam age to th e bea d area that cou ld
be res pon si bl e for pressure lea kage
(Fig. 4) .

Tire Rotation
Every owner's manu a l has a tire rotation diagram, and tire ro tatio n ma y
seem lik e motherhood and appl e

26

WHEEL RIM
DIAMETER

(Fig. 5) To avoid warping brake discs, tighten the lugs in a crisscross pattern with a torque wrench.

pi e- a lways good. H oweve r, thi s
subj ect is not so simpl e. Cost of ro ta t io n vers us longe r tire li fe is not a
prec ise equation. It depends o n th e
tires, th e driving, wheel a lignm ent
a nd suspension cond itio n. Further,
professiona l service is n ot always
exp ertly done. Un less th e lu g nuts
a re ti ghtened to specificat ions in
three eve n sta ges, using a crisscross
pat tern (Fig. 5) , the rotors may
become warped, w hi ch add s to main ten ance costs. If yo u let the mil eage
stretch o ut a bit, suc h as to 10,0 00
mil es or more , tires ma y deve lop

a lm ost imperceptible wear patterns
that w ill affec t rid e w hen th ey' re
moved to a new p ositi on o n th e car.
If yo u ca n 't ro tate th e tires often, yo u
m ay be better off leavin g them in
place and accepting the somewhat
sho rter tread life.
Some tire treads are directi o nal.
Th ey should rotate in on ly one directi o n a nd should not be rota ted
excep t by a profess iona l who can
demou nt them.
H ow ca n yo u tell if yo u ha ve thi s
type of tire? Look for a directiona l
ar row on the sidewall .

fI

MAINTENANCE BASICS

(

I

'~

EASY

Jumpstarting Your Car

t hits yo u like an electrica l shock just
as the airliner door sla ms a nd the
flight attendant oh-so-poli tely
instructs yo u to turn off yo ur cellphone.
Less th a n an hour ago, you parked your
car in the middle of a lO-acre a irport
parking lot, expecting the vehicle to
take YO Ll home when you return in five
da ys. Except yo u reali ze that yo u forgot
to turn off tbe headlights after your
predawn departure from ho me and t he
warning bLlzzer hasn't worked for eons,
if yo ur car has one. And if it doesn't,
there's no surpri se- yo u've done thi s
before. G reat. Now w hen YO Ll get home
yo u'll have to ca ll the a irport-approved
towing service and drop close to a hundred bucks for a jump.

I

JUMPSTARTING YOUR

CAR

Neglect Is Abuse
Lead-acid a utomo ti ve batteries are
ac tuall y remarka ble a t de livering
extremely high current for the few seco nds it takes to sta rt yo ur engin e, even
in extremes of heat a nd co ld . What
t hey are no t good a t is being able to
recover after delivering mo re modest
a mounts of current for a long time.
Irreversibl e chemi ca l changes ta ke
place. Specifica ll y, sulph a te need les
t hat bridge the separator between the
positive a nd nega ti ve pla tes for m
w hen a battery is deep ly discharged.
T hese needles no t on ly intern a ll y short
the plates, ca using a hi gh self-d ischarge rate, they also coat the plates
a nd interfere w ith the norma l lea d/s ul-

(Fig. 1) Make the last connection to a
ground point not on the battery to prevent creating a spark near any venting,
explosive hydrogen gas.

furic acid reactio n th at makes electricity to spi n your starter motor and run
yo ur fu el inj ectio n and ignitio n long
eno ugh to coax yo ur engine into life.
Before yo u do anyt hin g else, check
to see tha t the dead ba ttery isn't
frozen. Whi le a fu ll y cha rged battery
is a lmost freeze-p roof, a hig hl y disc harged battery ca n freeze w hen temps
hit the low 20s. If the battery has
them, remove the fi ller caps and look
for ice crysta ls in the electrolyte. Don't
try to charge a frozen battery. It wo n't

27

CHECK FOR IMPRINTED POLARITY MARKS

work, a nd will damage the battery
furth er. If you need a boost start to get
home, well ... life's like that.

Safety First

(Fig. 2) Make absolutely sure you've got the polarity correct
whenever you work on a battery. If your battery has side terminals, use these adapter bolts (right) when jumping it or use
jumper cables with clips shaped for side terminals.

HOW IT WORKS

Deeply Discharged Batteries
A lead-acid car battery, like any
battery, has an internal resistance, normally a few tenths of an
ohm. This means that a charging
voltage only a little higher than
the battery's normal 12.6 volts
will provide enough current to
actually charge the battery at
some decent rate, say, 10 to 12
amps. But as the battery discharges, its internal resistance
goes up. And the curve is steep.
When the battery is almost totally
discharged, internal resistance
can be high enough to prevent the
13.5 to 14 volts your alternator
puts out from doing any significant charging. Charging current in this instance can be as little as only a few
hundred milliamps until the battery's resistance goes down-and that might
take many hours, or even days of charging at normal voltages.
The answer is a high-voltage, high-rate professional charger that can
supply as much as 25 to 30 volts for a brief period to give the battery a
kick in the pants. This will generate a lot of heat, enough to cook a battery
within a few minutes. Leave this business to a professional, and follow up
with a normal 6- to 10-amp charge.

28

Your first task is to get jumper cables.
Preferably nice fat ones with a quality,
heavy-duty set of clamps . This is more
than just tool envy- there'S a lot of
current passing along those wires,
more than an arc welder, at least for a
few seconds. Resistive losses in the
cable can reduce the voltage available
to your stalled car's electrical system to
the point at which it will still be difficult to start, even with a healthy donor
battery and alternator adding their all
to the mix . It's important
to use fat cables and to
have good electrica l connections to reduce these
losses to a minimum.
A set of 6-ft. cables
won't do you much good
if you're parked nose-in to
a parking space-wlless you feel up to
pushing a 3-ton SUV back a truck length
to make the engine compartment available. Twelve or 15 ft. is better, which
makes using heavy-duty cables more
important because resistance losses are
proportional to the length of the cable.
Keep your cables clean and dry to
prevent corrosion from becoming a
high-resistance factor.

Doing The Deed
It's nitty-gritty time. You've got
cables, you've got a healthy donor car
available. Open the hoods and position the donor car nearby, so that
your cables will reach.
Some cars, like the one illustrated
on the previous page (Fig. 1), have a
remote positive terminal someplace in
the engine compartment. The battery
is mounted in an inaccessible area or
with its terminals inaccessible even in
the engine compartment. As for
where to attach the jumper cable, this
junction will be clearly marked and
covered in a red plastic sheath. If in
doubt, consult yo ur owner's manual.
Wear eye protection, even if it's
only a pair of sunglasses. Once in a
blue moon, a battery will explode

MAINTENANCE BASICS

(Fig. 3) If your car or RV is
in storage and chronically
needs help starting, a
trickle charger will keep it
ready and improve your
battery life as well.

TRICKLE CHARGER

in tb e reverse ord er. Was h
yo ur ha nd s if possibl e to
prevent a ny ba ttery ac id
fr om bleac hin g yo ur
cl othes or getting into
yo ur eyes .

when yo u try to jump it.
Options
Exp lode? Yes, explod e.
If yo ur RV or second car is
It's ca used by hydroge n
in storage for extended
gas, w hich is norm a lly
periods of time, the battery
vented by a ba ttery th at's
will self-di scharge . The
being charged or dissimplest solution is to use
charged at a high rate,
a trickle, or maintenance,
say, when you 're trying
charger (Fig. 3) . These
to start a car, the battery
chargers will automaticall y
runs down and yo u need
LEADS FOR
PERMANENT
adjust their charge rate to
a jumpstart. H ydrogen is
INSTALLATION
CLIPS FOR TEMPORARY CHARGING
a safe level, low enough to
expl os ive, and a sp ark
keep the battery at 100
fro m making a connecpercent charge without cooking it.
more wh en the dead car starts, but it
tio n can ignite it . It won't be a big
They're not recommended for charging
will help tbe donor car's battery sta rt
expl os io n, but it can cer ta inl y blow
dead batteries-just maintaining them.
yo ur engine a little if you give it a
the top of the plastic battery case off
If you're not in a cra shing burry,
quick shot of charge. If the dead car's
and spray acid into your eyes .
battery had enough charge left to make yo u might find cigar-lighter ca bl es
Co nnect the red clamp on one end
will get yo u sta rted (Fig. 4) . T hese
of th e jumpers to the positi ve termina l the soleno id click and run th e interi or
and in strument lights, then a minute or
ga dgets just plug into th e two ve hion the dead ca r. Verify th e pol a rity of
cl es' li ghter p lugs, p rov iding a modest
the terminals by the plu s sy mbo l
so is enough. If the battery was dead ,
leve l of ch arging, but not carr yin g
molded into th e battery case (Fig. 2) .
dea d, dea d, give it 5 minutes or so .
Don't just use the red terminalenou gh current to start a car with a
someone may ha ve insta lled an incortrul y flat battery. But if the engine w ill
Crank, Zoom
rect, red-colored termin al onto the
almost start, a 10- or 20-minute
N ow you ca n actu ally try to start your
dea d car. When the car starts, let it run
negative pole of the battery. Do the
charge will get you o n yo ur way, out
same on the p os iti ve terminal of the
at fast idle for another few minutes still
of th e wea ther and with cl ea n hand s.
donor ca r. Start the d on or car and let
connected to the donor ca r to continue
Remember that the lighter socket on
it idl e. Lights, bea ters, stereos and
cha rging by both alternators. Idling
the dea d car mu st be electricall y hot
rear-w indow defrosters- all electr ica l
provides onl y a modest charge rate, so
with th e key off, or yo u' ll need to
drains- should be off.
after a few minutes the best thing is to
turn o n the key in the dea d car to
If possible, cover the dead battery
dri ve the car at normal speeds for 30
compl ete the circuit.
with a shop towel or a sheet of cardto 60 minutes.
(Fig. 4) Minor
board. Any acid that man ages to bubRemove the jumper ca bl es
cases of won 'tble out o f th e vents will wind up on
quite-start will
the cl oth instea d of o n yo ur cl o th es or
answer to simple-to-use
the pa int on the fe nder.
lighter-plug
Connect to the negative terminal of
starters and
the donor car's battery with the black
jumper cables.
clamp. Verify the polarity. N ow connect
the remaining black clamp to the dead
car's engine block, an accessory mounting bracket or a p rotruding ear on a
manifo ld. Use the battery's negative termina l as a last reso rt. This procedure
will generate any sparks far fr om any
hydrogen gas venting from the battery
and reduce the risk of explosion.
Now wait. This will let the dea d
TO DONOR CAR
battery recharge slightly. It will charge

fI

JUMPSTARTING YOUR CAR

29

MODERATE

Repairing a Leaky Radiator

Y

o ur radi a tor is
lea king . Well , it
happens. If yo u
have n 't cha nged the
coo la nt o n a reaso na bl e
schedul e, it ca n beco me
corrosive a nd eat
thro ugh the ra dia tor.
Even normal shaking
a nd vibra ti o n w ill eve ntu a ll y ca use se pa ra ti o ns
bet wee n th e pa rts th at
a re connected by so ld er,
ep oxy or mecha nica l
crimps. Therm a l forces
fr om engines heating up
a nd coo lin g down ca n
ca use c rack s in stressed
a reas . Sea lin g gas kets
ca n co mpress a nd a ll ow
lea kage . And if yo u have a rea r-drive
ca r with a mec hanica l fa n and wea k
engine mounts, the engin e ca n lurch
forw a rd und er braking far eno ug h
for th e engin e-mounted fa n to " ki ss "
th e radi ato r. O r it co uld be ju st p la in
bad lu c k-a rock gets thrown up a nd
pun c hes a ho le in a tube.
Wh a tever its root ca use, a lea k is
genera ll y o bvious. But w hat to do
about the radiator? Repl ace it? After
all , today's ra di ators a re supposed to
be unrepaira bl e. Thi s is no t tru e at all ,
a nd th e best thing yo u ca n do is ta ke
o ut t he radi ator a nd bring it to a radi ator sho p fo r a free consulta ti o n. If it
ca n be repa ired, you ' ll not o nl y sa ve
mo ney, but th e repa ired origin a lequipment (OE) radi ator p ro ba bl y
will be a lot better tha n a new disco unt pa rt. It's no di ffe rent fr o m a ny
rebuilt a uto mo bile co mponent, except
th a t th e radiator has no mov in g p arts.
Everyt hin g star ts w ith re mov ing
th e lea kin g ra di a tor. Altho ugh do in g
so ta kes some ca re, it's a stra ightfo rward job. In the ea sier cases, yo u can
lift it o ut w ith shro ud a nd fan s
attach ed, th en compl ete the strip-

30

(Fig. 1) Loosen and slide
the hose clamps on the
hoses clear of the radiator
necks. Then, disconnect
the hoses.

prepared to do a co mpl ete dra in-a nd-refill , thi s
prelimin a ry step ca n help
prevent trapping a lot of
a ir in th e system. Air
bubbl es lea d to engin e
ho t spots a nd ping in
summe r o pera tio n, a nd
p oor hea ter o utput in the
w inter.
If there's an underbod y
pl astic cover a t the fr o nt,
remove it, even if it's not
necessa ry to do so to drain
the coola nt. With the cover off, yo u'll
surely be a ble to collect the draining
coo la nt w ith less splas h . You'll also be
abl e to get to th e lower radiator hose
more easil y, a nd you ca n inspect th e
lowe r end of th e radi ator as well. Yo u
might see a bolt-on connectio n to the
cond enser o r the support member that
yo u wo uldn 't otherwi se no tice . And
w ith most Ja pa nese cars, which have
downflow radi ators (tanks at the top

down o n the garage floor. And eve n in
a rea lly ti ght engin e compa rtment yo u
can usua ll y get it o ut w itho ut tou chin g the alc lines, or at w orst yo u
wo uld o nl y ha ve to unbolt the radi ato r from th e sa me module th a t ho lds
the alc co ndenser.
Begin by di sco nn ecting th e battery
gro und strap (even if th e ca r has beltdri ve n, ra ther th a n electrica l, fan s) .
The next step no rmally is to drain th e
radia tor, but befo re you do,
in spect both radi ator ta nks
(Fig. 2) If you have an electrical cooling fan, you'll
carefull y. If you find a
need to disconnect the wiring to it.
hea ter hose co nn ecti o n, as
o n a few ca rs, pinc h off th e
hose just a few in ches fr o m
the nec k, using loc king pliers . (If necessary, use a pa ir
of tongue depressors or
popsicle sticks between th e
jaws to get a good squeeze .)
With th e hea ter hose
pinched , yo u w o n 't lose
coola nt fro m th e hea ter
during th e drain . It can be
tough to get coolant to
compl etely fill the heater o n
som e cars, so unl ess you 're

MAINTENANCE BASICS

a nd botto m ), yo u' ll be abl e to reac h
a ny hoses or w ires th at yo u must di sconn ect from the bo tto m ta nk.
Rea d y? ow remove the press ure
cap, even if it's on a separa te ta nk or
on the engine. R emove th e radiator
drain p lug (or open th e dra in cock )
and let the radiator dra in. Move tb e
cl a mps off th e necks towa rd the mid po ints of th e radi ato r hoses (Fig. 1) ,
then di sconn ect th e hoses-in cluding
th e hea ter hose if there's a co nnectio n
at the radiator. If th e hoses are hea tsea led to the rad iator necks but in

.. ..

. .

REPAIRING

A LEAKY RADIATOR

good conditi o n, slip a thin sc rewdri ve r
between th e hose and nec k, a nd wo rk
it aro und to free the hose, th en twist
th e hose a nd wo rk it off. D o n't pry
w ith a large screwdri ver or yo u could
distort a meta l nec k or even crack a
plastic o ne. You may find it necessary
to ca refull y slit th e hose w ith a sharp
kn ife to get it to let go . Don 't sc ratc h
th e neck, or it' ll lea k in th e futur e.
As yo u di sco nn ect th e lowe r hose,
a fa ir a mo unt of engin e coo la nt is
like ly to fl ow o ut, so ma ke sure yo u
have a la rge ca tc h pan und erneath.

Eva lu a te th e ra di a tor in sta ll a tio n
a nd begin th e wrench work to fr ee it
up. A typica l app roac h is to remove
t he uppe r mo untlreta iner o n each
side, or the single support member
across the front. If there's eno ugh
clearance for th e ra diator to come up
a nd o ut with its shro ud and e lectri c
fans intact, just unp lug th e electri ca l
conn ectors for eac h fa n (Fig. 2) . If
no t, yo u' ll o ft en be a ble to just unbo lt
the shro ud a nd fa ns from the radiator
a nd tilt th em back to provide c lea ra nce to lift o ut th e ra diator.

.

.

31

(Fig. 3) A radiator shop can
replace a leaky O-ring seal, one
or both end tanks or the core relatively inexpensively.

tanks crimped onto the core. Your
nex t step is to take the rad iator to a
radiator shop that actu a lly repairs
plastic-tank ra diators. Th e Nationa l
Autom oti ve Radiator Serv ice Associati on (NARSA) has been giv ing its
members intensive training in the
repair of these radiators, whether
with copper/brass or al uminum cores ,
for several years (215/541-4500 ). So a
radiator shop sho uld know how to fix
it, and not simpl y try to unbox a
cheap new radiator and se ll it to yo u.
The chea p radi ators just don 't transfer hea t as well, and unl ess yo u can
get a spectacular price on a well-made
replacement, you're usually better off
with a repair.

Can it be repaired?

Disco nn ect th e overflow hose
and if th e reservoir is in the way, take
it out. T hi s can give yo u your first
close look at the reservoir. Many
reservo irs develop hairline cracks that
allow hard- to-t race lea ks, so if yo u
have a lea k here, yo u just ma y have
saved a bundle. If not, keep working.
If yo u have an au to matic transmi ssion, th e radiator usuall y conta in s an
autom ati c transmiss ion cooler. Disconnect the cooler lin es, a job that
isn't always a simpl e wre nch operation. In th e easiest cases, there's a
hose connecti on and a cl amp. In the
most difficult, tb ere's a quick-disco nnect fittin g th at requires a specia l (but
inexpe nsive) tool to separate. If YO ll
have a quick-disconnect, as on most
Ford products, and YO ll can't get the
tool , yo u'll find tb at the radiator end
of th e q uick-disconn ect has fittin gs

32

that threa d into the cool er. So a fittin g
ca n be unscrewed , but be ca reful. Use
a tight-fitting wrench and unthread
slow ly, so yo u don't dama ge the
quick-disconnect coupling.
W hatever type the cooler connections are, be prepared to plu g them.
Yes, yo u want to a void transmissionfluid leakage. But more critica ll y, if
any amount of coo lan t gets into the
cooler or its lines, it can be sayonara
for the a utomatic transmission. You
can plug a hose end with a bolt. Plug
a fitting with a rubber eraser, vac uum
hose plug or so me other cl ea n, soft,
flexible materi a l th at will stay in place
(but also come out easil y w hen yo u're
read y to reinsta ll the radi ator).
All clear ? Lift o ut the radi ato r and
strip off an y parts you were a ble to
leave in place. Virtually all late-model
ve hicl es have radiators with plastic

Almost a ll car, light-truck and
sport/ute radiato rs ha ve plastic tanks,
eith er with a luminum or copper/brass
core sections. They're precisely engineered to cool. And given today's tin y
grille openings or no-grille underbody
breathers, a cheap radiator is a bad
ga mble. It ma y look shiny new, but it
cou ld corrode and fail a lot faster
th a n a properly repaired unit.
When a radiator leaks, the most
conunon causes usually are readily
repairable at far less than the cost of a
new quality radiator. It certainly has
been true with the copper/brass radiators largely out of use. It's even more
likely with today's designs, particularly
aluminum-core radi ators, which can
run $200 to $400 for a first-rate
replacement. H ere are some repair
examples:
• Leaking gasket between plastic tank
and core: Th e shop uncrimps the
tank, install s a new gasket and
reet·imps the tank (Fig. 3) . It should
cost less than $75.
• Damaged tube (perhaps from a
stone): These can be fixed for an
extremely modest labor charge with
special epoxy or solder. Even aluminum radiator tubes can be soldered.

MAINTENANCE

BASICS

• Cracked plastic tank (per haps
from therma l st resses): A new tank
today is re lati ve ly in expensive for
most makes, so th e jo b should cost
less than $150.
• Leak ing header: The headers are the
metal pl ates at each end of the tubes.
The radi ator ta nk s attach to the headers, eith er by crimping a gas ket joint
or by so ld ering. O ld er Ford radiators
have epoxy sea ling between th e hea ders and th e tubes . If leaks occur from
cracked epoxy, a radiator shop can
remo ve the old epoxy and insta ll a
new sealing film using specia ll y
shaped guns and other tools. Th e cost
is typ ica ll y a bo ut $175 to $200 for
bo th ends of the r adiator, abo ut half
the pr ice of a new Ford radi ator.
• Fan " kiss" or corroded radiator: the
core is smashed in or leak ing from corrosion pinholes. If the tanks are good,
the shop can install a new core-perhaps even an OE one- and reuse the
old tanks, saving abo ut 25 to 30 % on
the cost of a new radi ato r. And the
resu lt shou ld be equal to a new OE
radiator. If the OE rad iator is an inexpensive design, then there won't be
much of a difference (perhaps less than
$75), and you might as well buy new if
it's in stock . However, one core fits

REPAIRING

A LEAKY

RADIATOR

many different sets of tanks, so stocking cores is simpler for a shop. Resu lt:
T he cho ice may come down to a new
co re that's availa ble now versus wa iting for a new radiator and having to
spend up to $100 more besides.

Putting It All Together
When yo u're ready to insta ll ,
inspect the rubber support bushings
for the rad iato r. Ma ny of today 's radi ato rs are held by mounting systems
that allow them to shake at a frequency tha t absorbs engine vibration.
Replace heat-cracked or oil-soaked
bushings. Otherwise, engine idle w ill
be rough a nd the radi ator may shake
itself into a leak . Clea n the threa ds of
o il-coo ler quick-d isconn ect fitt ings
a nd app ly Tefl on pipe sea ler before
reinstallati on.
If yo ur drained coolant was rela tively fres h, it's okay to put it back in
if it's not contaminated with dirt, oi l
or tran smi ssion fluid . Otherwise, use
a 50/50 coo lant/water mi x . If yo u've
ta ken thi s opportunity to flu sh the
system with water, th en add ha lf the
system's capacity of pure coo lant a nd
top off with wa ter.
Always check the carmaker's
instructions for filling a radiator-and

th en go beyo nd that an d add a littl e
more. Today's coo ling systems are
notorious for convo luted passages
th at ba lance heat transfer if the system is full, but trap air bubbles if not
completely fill ed. If there are air
bleeds, they must be open duri ng the
fi ll -up. Jack up the front of th e car to
raise the press ure-cap fill neck before
yo u pour in coo la nt. Even if the fi ll
neck isn't on the radia tor itse lf, the
higher it is, the better the system wi ll
burp air as yo u pour in coo lant. Make
sure the reservo ir level is correct and
that the air-sea ling gasket in the pressure cap is in good condition, so the
system won 't draw in air as the
coo la nt cools.
And " thermocycle " the system,
wh ich simpl y mea ns to warm it up,
then let it coo l down. Check the radiator coolant level when the system is
coo l, and top it off if necessa ry.
Once is not eno ugh. Keep check ing
eve ry day or so for a few weeks. Some
air purging w ill continue, a nd the system shou ld draw in add itiona l
coo lan t from th e reservo ir. The reservo ir level drops modestl y? Hey, th at's
th e way it's sup posed to work. Top it
off when necessary and you ca n conclude that all has gone we ll. (;

33

MODERATE

Curing Pulsing Brakes
he driver in the left la ne suddenl y rea li zes he's abo ut to mi ss
hi s ex it, so he cuts in fro nt of
yo u. Yo u mas h the brake peda l, and it
vibra tes like a runnin g cha in saw as
th e a ntil ock brak ing system (ABS)
keeps yo u o ut of a skid. Th a nkfull y,
you don't rear-end the jerk 's car, as he
al so bra kes to slow down. H e's o n th e
off ra mp a nd go ne, so yo u do n 't get
th e cha nce to pull a lo ngs ide a nd
express yo ur feelings w it h universa l
sign la nguage . But that's pro ba bl y a
good thing.
W hil e it can be reassuring to fee l
that ABS-co nn ected bra ke pedal pulsa tin g beneath yo ur firml y p la nted
foo t, it's reaso n to suspect a prob lem
if yo u ge t th e sa me peda l pul sa ti o n
with a li g ht to medium brak in g
app li ca tion.

T

th e titl es of a ll bull etin s fo r yo ur specific ma ke a nd m o del ca r.

ABS-esque

Lug Nut Torque

If the brake feels like the ABS is

The No .1 ca use of brake ped a l pul sa tion is uneve n lug nut torqu e. T he
usua l reaso n is th a t so me m ec ha nic
overtightened the w hee l lu g nuts w ith
a n impac t wrench, di sto rtin g th e
brake di sc.
How d o yo u kn o w if yo ur torq ue

cyc ling, but yo u k now th a t it's no t,
check the indi vidu a l axle trigge r
w hee ls in fro nt (a nd o n some ca rs a lso
in back ) a nd the adj ace nt w hee l speed
sensors. If yo u see a damaged w irin g
co nnector, bent sensor mo unting
brac ket or stone-damaged t rigger
whee l, that's a likely cause. But on
a lm ost a ll cars, th e ca use norma ll y is
something in t he service bra ke itself,
a nd the primary pro blems a re o nes yo u
usua ll y ca n check a nd correct yo urself.
Befo re yo u check eve n th e most
likely pro bl ems o n a late model, m a ke
a bso lutely sure there isn't a factory
probl em with a specific fi x . Sure, this
is low o n the " likely" li st, but it's a lo t
eas ier to look for a bull etin th a n to
pull w heels, etc. One poss ibility: th e
AIID a ta Web site, a lea din g sup pli er
of informati o n for profess io na l
mechanics (www.alldata.com ). If yo u
work yo ur way th ro ugh its consumer
information section and techni ca l se rvice bulletin s (TSBs), yo u ca n check

34

(Fig. 1) There's no
proper alternative
to torquing the lug
nuts in a crisscross
pattern, by stages
and with a torque
wrench. Oil the
threads and chamfer with engine oil.

w re nc h is acc ura te? Well , if it's by a
na me- br a nd too l co mpan y and hasn ' t been throw n aro und o r ha d a
ce ment bl ock dr opped o n it, it
sho uld be o kay. C heck th e torque a t
eac h wheel a nd comp a re th e read in g
w it h m a nufac tu rer's spec if icat io ns.
If th e re's a diffe re nce o f 20%
betw ee n a n y t wo lu g nuts, th a t 's too
mu ch. Tr y loosenin g a ll th e lu g
nuts, c lea nin g th e stud thread s w ith

MICROMETER

(Fig. 2) A micrometer is
needed to check that
each brake disc (new
ones as well) is a consistent thickness.
Check about 1 in. in
from the outer edge, at
six or eight equally
spaced places.

MAINTENANCE

BASICS

(Fig. 3) Borrow or rent a
dial indicator to measure brake disc runout.
Even a scant thousandth of an inch of
wobble will make your
right foot dance on the
pedal.

'Miking' A Disc

a wire bru s h, lightl y coa tin g t he m
and the nut c h a mfe r w ith cl ea n
engine o il , a nd th e n re in stallin g th e
nuts finge rtight.
Nex t, usin g a cri sscross pattern ,
(Fig. 1) ti g hten all of th em to a bo ut
o ne-third th e sp ec ifi ed rea din g, th en
to two-third s a nd fina ll y to the spec ifi ed torq ue.

Basic Diagnosis
If simpl e reti ghtenin g doesn 't fi x th e
prob le m , particu la r ly if a ll w h ee ls
were o ff to rqu e s pecs, yo u ' ll h ave to
pu ll th e wh ee ls for a c lose r in s p ecti o n. F irst, iso late t he pro bl e m to
th e fro nt o r rear w hee ls. Tr y dri vin g
the car a nd then s low in g or stopping w ith t h e parkin g brake leve r
li ghtl y pu ll ed up and yo ur fin ger o n
th e ratc het 's re lease button . If th e
ca r has a peda l parkin g brak e, tr y
app lyin g th at lightl y, but be su re to
pick a safe, d eserted parking lo t
w ith s m oo th pave m ent. If the car
s lows d ow n smooth ly to a stop, th e
brake p ro bl e m is in th e fro nt
whee ls . If th e car d ece lera tes in

CURING

PULSING

BRAKES

s urges , o ne o r more of t he rea r
brakes m ay be o ut-of- tru e.

Full Inspection
Ac tu a ll y in s pect ing th e w hee l a nd
b ra ke is th e nex t step. Make a lig nment m arks for th e w hee l and a lu g
stud before rem ova l so yo u ' re a b le to
in de x the rim to th e sam e stud . W ith
th e w hee l off, inspect th e ma tin g surfaces of the w heel and di sc hub surface . If th ey're packed w ith dirt or
bad I y rusted , c lea n th em th o ro ug h I y
(use 100-grit sa nd paper o r emery
cloth ). Rem ove sa ndin g res idu e w ith a
cloth and b ra ke solve nt. Lu be sparing ly w ith a nti se ize .
Look c lose ly a t both sides of th e
bra ke linin g contact surfaces o f t he
d isc . Moderate scores (too sm a ll to
snag yo ur finge rn a il on) are no t norma ll ya concern, but ru st o r o th e r
m ateria ls are (typica ll y brak e li ni ng
tra nsfer ). R ust o ften occu rs o n ca rs
t ha t sit for extended pe ri o d s in damp
clim ates w ith n o t-so-cl ea n a ir. Use a
fin er abrasive (2 00 grit) o n t he di sc
co ntact su r fa ces.

C hec k th e di sc for
un eve n th ic k ness,
using a mi c ro m eter
(Fig. 2) a t six to e ig ht
evenl y spa ced locati o n s on th e di sc, and
co mpare th e read in gs
wi th ma n u factur er 's
specs. As littl e as .0005
in . (th at's fi ve tenthou sa ndth s!) is th e
m ax imum , a nd yo u
ca n believe t ha t yo u ' ll
fee l a lo t o f d isc pu lsation a t .0008 in.
Sho uld yo u get th e disc
m ac hin ed? A lot of ev id ence says u n less a
sho p do es a good jo b
of m a inta ining its brake lat he, the
res ults often a re poor. And if the di sc
is cut too thin , it w ill war p eas il y in
se rvice . A bra n d-new di sc is th e best
ch o ice, but eve n th at sh ou ld be
chec ked for eve n th ick ness .

Measuring Disc Runout
M eas ure la tera l run o ut w ith a di a l
indi cator (Fig. 3) o n the linin g co ntac t
surfaces , on both sides, wit h the lug
nu ts reinstall ed and tig htened to
appro x imate ly 30 ft.- lb . T he ma x imum a mount o f run o ut shou ld be
.00 3 in . If it's m o re, ind ex- ma rk th e
ca li pe r to th e hub, a nd rem ove th e
ca liper a nd th en th e di sc. Ins pect th e
m a tin g surfaces of the disc a nd hub
and if there 's ru st , remove it w ith
ge ntl e us e of 200-g rit paper. A lso
rem ove an y d eb ri s a nd cl ea n th e surfaces w ith bra ke so lve nt.
Rota te th e di sc c loc kwi se o n e
stud , rein st a ll , tig hten th e lu g nuts
a nd rec heck. D o th is a coup le of
tim es to see if yo u ca n brin g rLlIlout
down to an accep ta ble le ve l (th e
prob lem m ay ha ve been produc ed by

35

plastic or metal sleeves. W hen yo u
re move the ca liper (Fig. 4), inspect
everythi ng. If the guide bo lts or p ins
a re corroded , rep lace them with
brand-new ones, lubed with silicone
grease (don't tr y cleaning them ).
D itto (incl uding silicone lu be) for
the sleeves if they're
corroded or crack ed, and
the bushi ngs if they a re deteriora ted.

PISTON

Rear Drum Brakes
(Fig. 4) Sloppy, corroded or deteriorated pins and their mating
bushings on some calipers can cause wobble and pu lsation.

fai lure to make a nd fo ll ow a li gnment ma rks a ft er so me ea rli er
serv ice procedure).
If yo u ca n't bring runout down
eno ugh, check the hub for runout.002 in . is the maxi mum. The thought
of repl acing the hu b may not be
appea ling, but unl ess run out is fa r
beyo nd reason and pu lsa ti o n is intolerab le, keep it in mind if noth ing else
surfaces as a possibility. A p rofession a l shop w ith an o n-car lathe may
(we repea t, ma y) be a ble to mach ine a
disc so th at it's referenced to the hu b,
to compensa te fo r a sma ll amo unt of
excess ive hub runo ut.

Brakes Not Releasing
W hen there's an uneven t hickness

pro bl em o n the d iscs at re lative ly low
mileage (under 50,0 00 ), acco mpa nied
by short lin ing li fe , it's poss ible the
bra kes aren't relea sing fu ll y, a ll owing
the shoes to stay in contact w ith the
di scs. A defective caliper piston
(sti cking when yo u try to p ush it
back ), a bad p iston sea l (no t retracting th e pisto n ) a nd a stick ing ca liper
are a ll poss ibili ties .
W hen th e ca liper does n't slid e
smoothly bac k a nd fo rth, th at's tro ubl e, and short lin ing life from fa ilure
to retract the shoes completely is just
o ne consequence. T he bra ke shoes
may a lso slap unevenl y aga inst the
di sc, anoth er ca use of pu lsa tio n.
Most ca li pers slide a long guide
bolts or pins, through bushings with

The rear drums are not as freq uent
a cause of pulsation as rear discs,
but if they're warped, or if the linings are no t making good contact, they
certainly ca n be responsible. Un less a
drum contact surface is bad ly grooved
(grooves here are not as acceptable as
on a disc ), you 'll need a dru m gauge to
check for taper or o ut-of-ro und. Or
as k a machi ne shop to measure it fo r
yo u, as the typica l shop will do it fo r
free or a nominal charge. Linings that
are worn very un evenly are a tip-off to
a drum that should be measured. Also
check fo r bro ken springs, or springs
that show obvio us signs of weakness
by allowing shoes to move easily.
Invest in a good torq ue wrench,
keep it in the trunk and use it to
ti ghten the lu g nuts in stea d of the lug
wrench w hen yo u have a fl at. Yo u
sho uld enjoy smooth modera te stops
fo r the life of the car. fI

HOW IT WORKS

Tire Imbalance
Tire imbalance, per se, shouldn 't cause a
pulsating brake pedal. Brake pedal vibrations are almost always caused by an outof-true condition somewhere in the braking
system. But on rare occasions it can happen. Normally, each tire has to be balanced statically first-i.e., so no part of
the tire is heavier and always sinks to the
bottom. Then they all need to be balanced
dynamically, so the rim doesn't wobble at higher speeds.
Any imbalances from either of these conditions normally
will manifest themselves as steering-wheel vibration,

36

,

not brake pedal vibration. Even a
tire with a high or low spot will normally be felt through the wheel.
But once in a great while you'll
find a tire that has inconsistent stiffness. Some parts of the tire's sidewall will be more or less easy to
deflect under load than others. This
won 't show up on the wheel balancer, but will make a brake pedal pulsate at a rate proportional t o your road speed. The diagnosis is to swap for
a different tire and see if the problem goes away.

J

MAINTENANCE

BASICS

MODERATE

Getting Your Car Ready For Winter
especially during damp
winter days. This m o isture ac ts as a conductor
a long a path th at normall y does n't condu ct
electricity at a ll, and can
leak enough current
between the battery
posts to prematurely
drain yo ur battery. In
fac t, co nsid er rep lacing
yo ur battery if it's mo re
tb an 4 yea rs o ld . Newer
cars tend to use sma ll er
ba tteries to red uce
weight and improve
mileage , and, combined
w ith high und erhood
tempera tures, th at spell s
Winter Takes Its Toll
an ear li er demise th an
The traditiona l tuneup is
yo u may have gotten 10
gone. Newer cars are large ly
to 15 years ago .
self-tuning, and do n't have igniWhile yo u're at it,
tion points or carburetors to
check all tb e electrica I
tweak . Factory-fill radiator
conn ections for loosecoolant in some new cars is
ness and corrosion. That
rated for five yea rs or far lo nger
(Fig. 1) Use warm water to clean the battery posts and
clamps. Use baking soda for stubborn sulfate deposits.
may mea n getting und erthan many peop le keep a car in
neath the ca r to see the
this age of low-monthly-payground strap a nd so leno id/s tarter
melted snow w ill infiltrate d irt deep
ment leases.
motor connections.
into th e fibers, th ere to remain forCars are still imperfect, m echa ni Check all light bulbs a nd repl ace
ever. Dump the as htray. Clea n the
cal contrivances, howeve r. Although
any that aren't wo rking. The d ays
w heel we ll arches and und ercarriage
many m a intenance re qui rem ents are
are short during the winter, and
reduced, there's still plenty of stuff
of mud a nd road dirt, so that sa lty
yo u' ll depend on th ese bulb s for visislush does n't soak into th em, providthat can break or fall off. An afternoo n of preventi ve ma intenance will
bilitya much larger propo rti o n o f
ing a perfect en vironm ent for rust.
grea tly reduce the possibility of bad
the day.
things happening. It 's a utumn-th e
Electrical
leaves are fa lling, but the weather is
While yo u' re cleaning, clean the batUnderhood in General
still relatively warm. A couple of
tery with warm w ater. Remove th e
Still in an electrical mode, check the
ho urs of maintenance w ill be a lo t
terminals and w ire brush them and
alternator connections and mo unts
easier to take now than a couple of
the battery posts with warm water
fo r looseness and evidence of overhours of repa irs when yo u have to
and ba kin g soda (Fig. 1) . Reattach
hea ting. High electrical demand s for
shovel yo ur wayan ext ra 50 ft . to
th e termin als and coa t a ll exposed
lights, hea ter fa ns and rear-wind ow
work in an unh ea ted garage.
metal with petrol eum jell y. Yo u're
defrosters, as we ll as recharging a batnot do ne yet-u sing so me sort of
tery ab used by coaxing a reluctant
The Easy Stuff
ho useho ld cleaner, clean a ll traces of
engine to life, can make a margina l
Clean. Clea n out the interior and the
dirt and o il from the battery's top
connection overheat.
trunk . Shampoo the carpets and the
a nd sides, particu larly near the termiCheck accessory belt condition and
seats , beca use a winter of slush an d
nals. Traces of dirt can tra p moi sture,
tension, beca use that extra electrical

now covers yo ur car.
After 10 minutes of
shoveling snow and ice
from the roof and w indows (not
to menti on 30 minutes of shoveling the dri veway), yo u' re rea dy
to go to work. Twisting the key
languidly brings the engine to
life, much to yo ur relief. But ...
th e windshield wipers leave
strea ks, th e washers drizzle fluid
inches short of the glass, the battery light flickers and the heater
fan blows little a ir of any temperature. Not a particularly
good da y for even a late-model
car that's been neglected.

S

GETTING

YOUR

CAR

READY

FOR WINTER

37

(Fig. 2) Check belts for proper
tension using a tension gauge.
Serpentine belts can also be checked
with a gauge, although they aren't as
likely to be loose.

dema nd will strain a ma rgina l belt
(Fig. 2) . Man y modern ca rs have a single se rpentine, a utomatica ll y tensioned
belt, but it still can fr ay a nd come off.
C heck a ll rubber hoses . Five
years, in th ese t im es o f a ir po llut io n
a nd hi g h und erh oo d tempe ra tures ,
is a leg itim ate life spa n fo r a rad ia-

to r hose. If o ne seem s sq ui sh y, brittl e o r ju st s uspect, now wou ld be a
goo d tim e to replace th e m a ll.
C heck th e d a te o n the coo la nt.
(Re membe r many new cars have
ex tended dr a in inter va ls-but no t
p e rm a ne nt coo la nt. Rea d th e ow ner's
ma nu a L) [f it's du e to be rep laced ,

use a 50 -50 mi x of fr es h coo la n t a nd
wa te r (Fig. 3) .
Co nsider cha ng ing yo ur tra nsmission fluid, differenti a l lu brica nt a nd
brake fluid if yo ur ca r is more th a n 3
yea rs o ld. Lubri ca nts brea k d ow n,
a nd brake fluid a ttrac ts mo isture a nd
d eteri o ra tes . At a ny ra te, check th e
leve ls, and d o n't forge t the p ower
steer ing rese rvo ir.
F ill the w ind shield was her ta nk
w ith was her fluid. C heck the pump
a nd nozzles fo r a hea lth y, we ll -a im ed
sp ray pattern. Ma n y nozzles ca n be
re-a imed b y in se rt ing a pin into th e
nozzle to use as a ha nd le.
Winds hie ld w ipers are esse nti a l for
w inter driving, a nd afte r a SUJllm er of
sun shin e, th e rub ber sq ueegees are
probab ly in so rr y shape . Pl ay it safe
a nd replace th em. Be sure th e w iper
arms a nd sp rin gs a re in good shape,

HOW IT WORKS

Oil Viscosity
Fall is a good time to change oil and filters. Check your
owner's manual for the rating and viscosity, but most
cars nowadays use an SL-service rated oil. This rating is
some measure of the oil 's longevity and resistance to
oxidation and evaporation. SL oil is fine for older engines
that specify an SG- , SH-, or SJ-rated oil, because the rating always improves when a new one is introduced. The
SAE viscosity rating is a measure of how thick the oil is.
All modern cars should use a multigrade oil, probably a
5W-30 or lOW-30. The W in these ratings stands for a
winter viscosity. A multigrade oil will be as thin as
the thinner (5W- or lOW- rating) when the engine
is first started. This will allow oil to flow more
rapidly and lubricate parts that have had all the
oil drain off of them overnight. A thicker oil
might not be pumped to remote parts of the
engine rapidly enough. On the other hand , a
thicker oil (the second number in the rating)
will resist becoming too thin when the engine
reaches operating temperature. The American
Petroleum Institute is an industry watchdog and
oils bearing the API emblem can be expected to
meet their specifications.

38

In spite of what your brother-in-law the shade-tree
mechanic tells you, don't use a heavier grade of oil just
because you used to in your older car. Modern cars were
engineered to use 5W-20, 5W-30 or lOW-30 oil yearround. Check the owner's manual to be sure. The lighter
oils are also better on fuel consumption and can significantly improve mileage.

When buying engine oil, check
for API certification and SAE
rating.

MAINTENANCE

BASICS

a nd th a t th e bl ad e is held squ a re
to th e w indshie ld surface . You
may need to bend it sli g htl y to
keep everyt hing sq ua re.
C hec k th e a ir cl ea ner, a nd
consider replacing it and the
fuel filt er (if yo ur ve hicl e has a
repl ace ment type, no t the perm a nent one in the gas tan k) .
Th e fu e l filte r w ill tend to trap
wa ter, and o nce it tra ps eno ug h,
it w ill fai l a nd may dum p so me
accumu la ted dirt into yo ur fu el
inj ection system . And winter, o f
course, is w hen yo u tend to find
the most wa ter in gaso lin e at
th e pump.

bial dared 6-yea r-o ld's tongue
sti cks to a frig id fl agpo le.

Rust Never Sleeps

Befo re the sa lt tru cks come o ut
is a good tim e to ge t out th e
to uch up pa into Use it to cover
a ll th e bare metal at the bo tto m
o f a ny sto ne c hips a nd parking
lo t dings. C lea n rh e c hipped
a rea thorou g h Iy, a nd use a
too thpi ck or a ma tch to ap pl y a
touch of zin c- rich primer to the
bare metal. All ow this to dr y,
a nd chase a ny overlap back to
th e lip of th e scratch with lacquer thinn e r. Th en ca refull y fill
(Fig. 3) In spite of long-life coolant in many new
cars, eventually you'll need to drain and refill with
th e chip w ith to uc h up paint.
fresh
coolant mix.
It' ll shrink, so yo u may need
Where The Rubber Meets
seve ra l a ppli ca ti o ns to build up
The Road
th e leve l of pa int to flu sh .
ca lipers a nd sliding pins. Wh il e th e
Dri ving in snow d ema nd s goo d tires.
Be sure yo u ha ve a d eq uate tread
w hee l is off, pu ll th e pa d s out of the
ca lipers and be sure everythin g is slid- On the Road
d ep th, a nd consid er changing to
ing free ly. Wire brush sliding-key
snow tires if yo u li ve in a heavy snow
Even a perfectly running car ma y
w ind up stu ck in a snowbank. So put
a rea. Go a hea d a nd pick up a set of
ways a nd pin s that let t he pa d s pull
bac k from th e di sc when yo u remove
in expe nsive stee l w hee ls a t th e loca l
together a kit of essenti a ls for yo ur
sa lvage ya rd for yo ur snows in stead
yo ur foo t from the brake. Exerc ise
trunk. This should includ e flar es, a
of hav ing yo ur tires remounted and
the p isto ns b y push in g t hem back
fl as hli g ht, jumper cables (if only to
ba la nced eve ry fall a nd sprin g. And
into th e ca lipe rs and th en press in g o n
help so me unfo rtun a te so ul w hose car
whi le th e ca r is up on th e sa fet y
the bra ke p ed a l once o r tw ice to
was n't winterized li ke yo urs), a fo ldsta nds, inspect th e suspension bushbreak up corrosion between th e pising ca mp shovel, kitty litter for tracings, control a rms, ba ll jo ints a nd tie
ton a nd the ca liper.
ti o n, a ca n of gaso line anti-freeze, a nd
rods, a nd th e brakes. Now wou ld be
Again, it's a lo t eas ier to look a t
tire chains if th ey ' re lega l in yo ur
a good tim e to replace t he bra ke pa d s
thi s stuff o n a c ri sp a utullln da y than
sta te. If yo u eve r tra ve l outs ide o f
if they are more than 60 percent
it is to try to fi x it so me sub ze ro
urba n a reas, a co up le of blankets a nd
worn. Even if th ey a re no t, chec k
mornin g when a ll of yo ur wrenches
a ce llph o ne or CB rad io o ug ht to be
carefu ll y fo r co rrosion around th e
stick to yo ur fin gers li ke the proveron boa rd as wel l. ~

GETTING YOUR CAR READY FOR WINTER

39

EASY

Repairing a Flat Tire
pressure or flat. Driving m ore than a
few feet w ith the tire at zero inflati on
pressure may ca use the rim to go uge
th e inner liner, damaging the body
cord . Driving at mo re tha n a wa lk
w ith th e tire a t very low pressure ma y
build up eno ugh heat to damage the
sidewall beyond servicea bi lity (Fig. 1) .
The portion of the nail or wire that
entered th e ti re's interior may have
fl ailed aro und and ripped the inner
liner or plies (Fig. 2) . After in specting
the tire, th e technici a n may app ly a
proper patch , remount the tire a nd
rei nfl a te it.

Here's How

here's rarely a more welcome
sight tha n the insid e of a warm
garage late at night, as yo ur
door ro ll s open to we lco me yo u and
yo ur fam il y ho me after a t rip o ut of
'
town. Partic ul arly to night, beca use
you're far la ter than expected. Fla t
tires are genera lly no more tha n a nui sa nce-but t hi s time yo u found yo ur
spare tire to be as flat as yesterday's
beer. Fortun ately, a nice yo ung gentlema n working in a gas station o nl y a
ha lf mile up the road man aged to plug
yo ur tire w ithin a few minutes. Yo u
watc h the inflati o n pressure of the tire
for a week or so, a nd everything
seems fine.
Until a few weeks la ter. Then the
sa me tire disintegra tes suddenl y o n
th e intersta te in heavy traffic. You
ma nage to ma intain control of yo ur
SUV by lifting partway off the thro ttl e
a nd gingerl y steerin g ove r to the
sho ulder, ignoring the cacopho ny of
th e fa iled tire as it fl a ps violentl y in
the w heel we ll , shedding parts as it
tears into pieces . It's not just flat, it's a
smoking ru in , and there's substantial

(Fig. 1) This damaged area inside the
sidewall was caused by driving the tire
when it was flat.

da ma ge to yo ur w heel well 's sheetmetal to boot. Obv io usly, th ere was
mo re damage to yo ur tire than met
the eye-and the ni ce fellow w ho
repaired it for yo u didn't necessaril y
do yo u any favors.

The Right WayAnd The Wrong Way
The tire indu stry has a rule a bo ut
externall y pl ugging a tire w ith a
worm. Don 't. It's a qualified exclusio n, a nd we ag ree with it, for good
reasons. An externa ll y a pplied worm
might be an acceptable emergency
get-home-tonight quick fix, but a
properl y trained tire techni cia n must
late r co mplete th e repa ir by remov ing
the tire fro m th e rim a nd do ing a
co mplete inspecti o n of th e tire for
additio nal p unctu res and damage.
Damage ca n come from no t o nly th e
na il o r w hatever caused the air loss,
but a lso fro m runn ing the tire at low

Okay, we doubt many readers w ill
ever repa ir a flat them selves beca use it
in vo lves some pretty exp ensive tools.
However, we've done it w ith nothing
m o re t ha n hand too ls and a 12-vo lt
portabl e compressor, a nd more than
once, too . Once, it was late a t night
a nd we didn't wa nt to wa it for the ti re
shop to open. Ano ther time, it was
beca use we were in a very re mote
area, a nd a trip to tow n was nearly a
two-d ay hike.

Busted
Wheel/tire assemb ly off the ca r ?
(We've do ne it with the rim still
bo lted to the axle of a trail er but it 's
to ugh work.) Start by inflating the
tire a nd subme rgin g it in water to
look for bubbl es . Now ro ll the tire
a long th e gro und in a good li ght to
look for the pun cture. Cha lk a ny
suspic ious ho les in the trea d, even if
there was no stream of tin y little
b ub bles associated w ith it. You'd be
a ma zed at how m a ny times tires a re
take n in for repa ir w ith multipl e
punctures . Make a c ha lkm ark o n th e
ti re sid ewa ll next to the va lve stem ,
because the ti re sh o uld be reinstalled
in the sa m e ind ex. Now yo u can
remove the val ve core to completely

M A IN TEN A NeE BAS I C S

40

DAMAGE NOT
VISIBLE FROM
OUTSIDE OF TIRE

(Fig. 2) An innocuous-looking nail
through the tread
may have damaged the inside of
the tire.

deflate the tire a nd demo unt it .
Next, with a bright light, carefully
inspect every sq uare inch of the
inn er lin er. Pay particular a ttention
to the areas inboard of th e cha lkmark s yo u've mad e. Look fo r damage caused by the fore ign object.
Such a ho le may be p atched if the
object has n 't d amaged any cord,
although a ny exposed cord usually
mea ns t he tire shoul d be scrapped .

Also look for p eripheral damage
ca used by the tire being pin ched
between th e rim a nd the pavement.
Any da mage to the inner lin er th at
came a bo ut as a resu lt of friction by
being p inched a nd then dr ive n makes
the tire a likely ca ndidate for immediate rep lacement.
Any punctu re through th e sidewa ll
of the tire a utomatica lly means the
tire needs to be scrapped.

Remove any fore ign o bj ects in the
tread by grasp ing th em wi th p liers
a nd ya nkin g th em o ut. Make no te of
t he angle the objec t ma de to t he surface of th e trea d . In fac t, yo u sho uld
take a thin probe, lik e an aw l, a nd
probe the ho le stra ight through in to
t he ins id e of the tire. Look for evidence of cut cords or separated
pli es, beca use they' ll be sti ck ing o ut
of the ho le.

HOW IT WORKS

Run-Flat Tire
A few late-model cars come
equipped with tires that can be run
without any air at all, at least far
enough to get to a place where
they can be repaired. These tires,
available from several different
manufacturers, can be retrofitted
to any car that uses an appropriate
size tire. The sidewalls of these
tires have an extra piece of molded
rubber near the bead. This rein forcement is stiff enough to keep
the rim from contacting the inside
of the tire, even under cornering
and braking. The tire and auto
manufacturers specify an upper

REPAIRING A FLAT TIRE

Run-flat tires' bead reinforcement
provides stiffness to keep the bead
seated on the rim and prevent
sidewall damage.

TREAD

BEAD

limit on speed-usually 50 or so
miles per hour-and a maximum
range-often 50 or 100 mileswhen the tire is deflated. Because
the performance of these tires
with zero air pressure is so good,
tire manufacturers require any car
fitted with them to have a tirepressure monitoring system that
will alert the driver to the fact that
he's driving on a flat.

41

(Fig. 3) A tubeless t ire puncture can
be properly repaired only by breaking
the tire off the rim and pulling a
stem-type patch through the t read
from the inside.

Straight Holes
If the ho le ma kes a 25 " or sma ll er
a ngle to th e tread , t he correct p a tch to
use is a " mushroom " pa tch (Fig. 3) .
The head of the mu shroo m provi des a
good a dh es ive sea l to the tire's inn er
liner for pro per a ir retenti o n . Th e
stem o f th e p a tch se rves severa l p urposes . It plugs th e ho le to a nchor th e
p a tch a nd , in concert w ith the c hemi ca l vulca nizing cem en t, prevents
wa ter fro m entering th e ho le and
w orking its way into the tire's trea d .
Using a proper tire rea met; clean out
the hole fro m the inside o ut (Fig. 4) .
Aga in , look carefull y fo r evidence of wire
o r tire cord . T he rea mer w ill remove any
road dirt o r o il and all Yda maged rubber fro m the ho le, leaving a fresh rubber
surface for bonding the cement.
Center the p atch over the ho le
inside t he tire, a nd mar k a ha lf-inch

42

(Fig. 4) Thoroughly ream t he puncture t o clean the rubber and provide a good bond.

a ro und its perip hery w it h cha lk. Use a
tire bu ffin g too l to remove t he surface
of t he ru b ber a nd leave a sm ooth texture. A power buffin g too l is best, but
a ha nd sc raper w ill wor k . Do n't b uff

thro ugh the lin er into the p ly rub ber
or th e cord . Bru sh, blow or vac uum
t he ru b ber dust a w ay from the buffed
area . D o n't to uch this area w ith yo ur
fi ngers o r a rag .

MAINTENANCE BASICS

Coat yo ur awl liberall y
with cement and run it in and
out of the hole several times to
carry the cement throughout
the hole. Leave the awl in the
hole until just before installing
the patch so the cement stays
liquid. Remove the peel-off
tab from the patch, and put a
single coat of vulcanizing
cement on the head of the
patch and the buffed area.
Allow this to dry thoroughly,
and don't touch the cemented
areas because the moisture
and oil in your fingerprints
will prevent good adhesion.
Lightly coa t the stem of
(Fig. 5) Oblique punctures require a different plug.
the patch with cement. Pull
our the awl , and pull the stem
of the patch through the hole. Stitch
patch. This involves reaming the hole
the patch (using a tire patch stitching
and installing a rubber stem with
tool) to the tire from the middle out to
cement. The stem is then trimmed
prevent any a ir bubbles fro m being
flu sh with the inner liner, the area
trapped under the patch. Now cut the
buffed and a patch is cemented over
protruding stem off nearl y flush with
the top of the stem.
the surface of trea d rubber.

Back On The Road
Oblique Holes
If the hole isn't within 25 ' of vertical
(Fig. 5) , yo u' ll need to use a two-piece

REPAIRING

A FLAT TIRE

Before remounting the tire on the rim
(a jo b for a professional with specia l
equipment), take a hard look at the

rubber va lve stem. If it's
weather-beaten, damaged o r
just more than about 5 years
o ld, pop it o ut and pu ll in a
new one. Use the correct
diameter and length, and a
valve core that matches.
Valve stem caps aren't there
to simp ly backstop the valve
core's air retention-they
keep moisture and dirt out of
the stem and out of yo ur tire.
Reinfla te the tire. Use
soapy w ater to check the
beads, va lve stem and the
repair for leaks . And keep a
close eye o n yo ur tire for a
few weeks, both by monitoring the a ir pressure a nd looking for evidence of delam ina tion or a belt failure. A failed belt
usually will cause an out-of-round
condition and the ride will often indicate it.
Ca n you adequately repair speedra ted tires? So me ti re ma n ufacturers
di sagree, but at leas t o ne (Goodyear)
says yo u ca n . They do specify th at
there can be on ly a single r epair, less
than one-q uarter inch in diam eter,
per tire. (I

43

MODERATE

Servicing Your Ale
t's hot, so hot yo ur car's interior
juice is getting to the clutch by probHowever, after the system has been
shimmers. Getting into the car is
ing its wiring connector with a 12shut off for a few minutes, pressures
clearly out of the question, at
volt test light (Fig. 2) . If the light
equa lize, so you can check pressure at
least until the air conditioning hau ls
doesn 't go on, there 's a break in the
both of the service valve ports (one
out a few million BTUs. You lean in
circuit. If it does go on brightly, attach low-pressure, one high-pressure).
and twist the key, being careful not to
a jumper wire to the ground side of
They should be the same-rough ly
raise blisters by touching the steering
the clutch circuit. If the clutch sti ll
equal to the ambient temperature.
wheel. The engine fires
If pressure is less, the
and idles smoothly, then
refrigeration system is low
you punch the max cold
on refrigerant, and that
button on the dashcould account for the failnothing happens.
ure of the compressor to
Great, you think, at
engage. Have a profesleast in the old days, ordisional trace the leak and
nary folks used to be able
then recharge the system
to purchase R -12 refrigerwith refrigerant. Incidenant to punch up a tepid
tally, if the service va lve
air cond iti oner. Not anyca ps are missing, they
more. And it won't be too
could be the cause of your
long before R-12 is off the
loss, as they provide the
GAP
market completely- a vicreal sea l, not the valve
tim of federa l regulations
itself. Warning: Do not try
that restrict the manufacto seal leaks withalc sea ler
ture of ozone-depleting
prod ucts-period.
chlorofluorocarbons.
(Fig. 1) Gap between hublplate and pulley should close when
Important: Use only Ralc is turned on.
Fortunately, it's still
12 in an R-12 system, Rpossible for the average
134a in an R-134a system;
Saturday mechanic to fix some of what won't engage, it's bad.
never mix the two! Right now, there's
ails his air conditioner without having
It takes special tools to change a
still some R -12 around, so you might
to open up the system. To keep you in
compressor clutch. Unless you can
want to keep the system on R-12.
However, if you ever have a compressor
the service picture, let's consider just a
rent them, leave this job to a pro.
few of the common causes of poor-or
If the clutch engages when you jump failure, the replacement will likely be
compatible with R-134a, which would
it, there's a problem with the ground
zero---cooling that you can diagnose
make changing over to the new refrigand cure. Start by acquiring the alc ser- circuit, which may be wired through to
erant simpler. But th is is not do-it-yourthe engine computer. Both circuit probvice manual and electrica l schematic
self work. It takes special equipment.
lems require straight electrical diagnofor your vehicle. You'll also need a 12The alc pressure is normal? Apparsis and a good wiring diagram.
volt test light. A volt-ohmmeter comes
ently, the problem is purely electrica l.
However, the refrigeration system
in handy as well.
And in this case the first step is to
may also be involved. There's a lowcheck for a computer trouble code.
pressure switch in the current-feed
No Cooling
The engine computer? You bet. On
circuit that is designed to keep the
If the compressor doesn't engage,
compressor from engaging when pres- most American cars and some
there will be zero cooling. An electroimports, turning on the air conditionsure is low.
magnetic clutch shou ld lock the drive
ing at the dashboard is just a request
See if there's enough refrigerant
hublplate on the compressor (Fig. 1),
to the engine computer to provide the
pressure to close that switch, which
with the belt-driven pulley to spin the
electrical ground to complete the comrequires pressure gauges, and hoses
compressor shaft.
pressor clutch circuit. If the engine
The clutch circuit is fused, so check that attach to your system. When the
system is running, one half operates at computer sees a reason not to, the alc
the fuse. The fuse is good? With the
won't come on. Possible reasons, in
low pressure and the other at high.
engine and the alc on, check to see if

I

44

MAINTENANCE BASICS

addition to low refrigerant, include
warning signa ls from certa in engine
sensors . The coo lant-tempera ture sensor may be signaling a very high
coolan t te mpera tu re, and a ll owing the
ale to come on could ca use overheating. O r a power-steering switch may
be signaling high pressure (as in a
parking maneuver ), and all owing the
alc to come on could add to the engine
load fro m the belt-drive n accessories
and sta ll the engine . Of course, some
of these signa ls may be wro ng, and
yo u' ll need to investigate the so lu tion
to these engine pro bl ems to get the alc
online aga in.
No comp uter tro uble codes? C heck
fo r a bad alc clutch relay. Also, note

SERVICING YOUR

AIC

tha t some of the comp uter sensors are
not covered by tro uble codes-the
power-steering sw itch is a common
exa mple. If yo ur car has one, bypass it
for tes ting. If th e compressor now
comes on, rep lace the switc h.
No cl ues in th e comp uter circ uit ?
Refer to an ale circ uit diagram to see
what ad ditional switc hes or relays are
in th e co mpresso r-c lu tch circ ui t. On
many cars of a ll makes (particul arly
R-12 systems), there's a sw itc h that
cycles the compresso r clu tc h on and
off to co nt rol performa nce. You ca n
fin d out if the switch is ba d by
un p lugging it and attac hing a jumper
wire across its connector. If the compressor now comes on, the switch

(Fig. 2) Use a 12-volt test light to probe
the alc compressor's clutch wiring. If
the clutch isn't pulling in, there's no
cooling.

apparent ly isn't clos ing. Confi rm thi s
with an ohmmeter acr oss the sw itc h
ter minals. O n GM and Ford ve hicles,
the switch us uall y is on a large cy li ndrica l can ca ll ed the acc umul ator. On
ma ny C hrys ler prod ucts, it's in a
block at the fi rewa ll.
Ba d sw itc h? O n late-models, the
sw itch is mo unted on a Schrader
va lve. As yo u unt hread the switch, the
va lve closes so yo u wo n't lose any
refrigerant. Grease the new O-ring
w ith minera l o il, gently pos ition it on

45

the port and then thread
the new switch in to
pl ace. 1£ the switch has a
plastic body, a firm
hand-tightening is
enough . With metal, a
gentle nudge w ith a
wrench does it, beca use
the O-ring makes the
sea \.
Note: Your circuit
diagra m ma y show other
pressure switches. The
variety is almost endless,
depending on the type of
vehicle, so without a
diagra m, yo u're in Guess
City. Among the most
common va riety are a
high-pressure cutout and a dedicated
low-pressure cutout (often in addition
to the cycling clutch switch). If the
basic pressure check showed nothing
awry, unplug and bypass these switches

for testing. In most cases, the bypass is
achieved with a jumper wire acrosS the
wiring connector terminals-but read
the wiring diagram details, as some
switches are normally closed and open

up as a signal. If so,
simply unplug these to
bypass. Double-check
each switch with an
ohmmeter.
Ma ny cars-particularl y Japa nese models
and many late-model
Chr ys ler products-use
a temperature sensor
o n the evaporator (th e
in-car hea t exchanger
that cools the inter ior
a ir) in conjunction w ith
an electronic module to
cycle the clutch. The
shop m anual should
provide specifications
for a resistance check
of the tempera ture sensor and
w here to connect a voltmeter to test
for an output signa l to operate the
clutch. Make these checks under
the das hboard .

Poor Cooling

.. -- ..... - .... ..

_-

The temperature of the
air coming o ut of the
registers w ill not necessarily be very low on a
humid, hot day. The alc
may expend all its effort
just wringing humidity
out of the air, and the air
blowing out of the registers easily could be as
high as 60° to 65°F. If
there is some cooling,
but clearly not a normal
amount, make this simple check: Is the front of
the condenser (the heat
exchanger in front of, or
alongside, the radiator)
free of bugs, leaves, road
film and other debris? If
it isn't, airflow is
restricted. Clean the condenser with a soft brush
and a detergent-andwa ter solution (Fig. 3) .
(Fig. 3) Use a soft brush
and detergent to clean
leaves and dead bugs
from the condenser.

MAINTENANCE BASICS

46

ma nce as a nyt hing. If th e
If yo u've got a car that has
either no grille or a tiny o ne,
bl ower simpl y won't reac h
you've got a n " underbod y
high speed, check the circuit
diagram for a hi gh-speed
brea th er." Inspect a ny underbody a irdams a nd covers.
bl ower rela y. You might be
a ble to fix a bad connecti o n
If they're damaged or missing,
by simply plugging in th e
they could be responsible for
w iring connector properl y. Or
reduced airflow and poor coo lyo u may find a broken wire
ing. And on a lmost all cars,
by pro bin g tb e w ir in g co nn ecwhen t he a ir cond iti o ning is
tor wit h a test light.
turned on, a radiator/conAnotber common ca use of
denser electric fan should a lso
poor performance: the hea ter
come o n. If it doesn't, th at also
core's bigh temperature is
red uces airflow and a/c perform a nce, particularly in slowbleeding into w hat sho uld be
driving conditions.
purely chilled air from th e
Of course, if the a irfl ow is
evap orator. Some hea t tra nsfe r
is normal if yo u move the temnorma l, you'll wa nt to make
(Fig_ 4) Bubbles in the sight glass may mean the air
pera ture lever or turn t he knob
sure a parti a l loss of coo la nt
conditioner is undercharged. Have a professional (using from the max co ld pos itio n.
is no t responsib le fo r a drop
special equipment) recharge.
in performance. Some o lder
However, a t max cold, t here
Japanese-made a nd some
should be no hot-air bleed .
Chrys ler systems (with R-12
C la mp off a hea ter hose to
refrigerant) have a sight
block t he h o t-coola nt fl ow
glass- a tin y w ind ow into the
(Fig. 5) . If ale performa nce
refrigera tion circ ui t . C hec k it
improves cons iderab ly, o ne
to see if there are a ny bubbles
of tb e fo ll ow in g co uld be
w hen t he clurc h is engaged
occ urring:
(bubbling w hen it's di sen• A hea ter coo lan t-flow va lve
gaged o r in th e first few sec(used on many bur not a ll
onds after engagement is norve bicl es) is stuck in the open
mal ). Bubbles with th e clutch
p ositi on.
engaged may- repea t, may• The flap door that's
indica te a low c harge (Fig. 4) .
supposed to reg ul ate the a ir'., '
Also, check ope rati ng presflow t hroug h th e hea ter or
sures wi th a pressure ga uge
evapora tor isn't opera ting
a nd co mpare them w ith facproperly. If it's a manu al,
tory specifications. You must
cable-controll ed type wit h a
use the specs beca use preslever, tr y slamming the lever
sures vary w idely with amb i(Fig. 5) Clamp off the heater hose with padded Vise-Grip aga inst the max cold stop.
ent tempera tures.
pliers to check for a leaky flap.
H yo u don't hear a flap doo r
As exp lained ea rlier, a
hit a stop inside the underd as h
p ower-steering switch may mi sbetio ning system has an eva pora tor-te m- case, the ca ble ma y
have, signa li ng " high press ure" w ith
perature sensor, take a ca reful o hmneed adjustment. W ith a n electric
just a sli ght rise in pressure, t hu s
meter read ing a nd convert it to
motor-driven design, check the case for
killing th e a/c. If yo ur system runs fine
degrees by consulting the table in the
a bad wiring connection a t the mo to r.
with the car parked, but stops as soo n
manual. You ma y find that the sensor
And, of course, there ma y be co ld
as yo u pull away, either a bad powert hin ks it's co ld w hen it's really not.
air, but in the wrong place. If the co ld
steering sw itch or a mi sbe hav ing
H t he air blow ing in your face
air is going to your fee t or o ut of the
thro ttle-position sensor (TPS ) is poss iis coo l, but t here isn 't eno ugh a ir
defrost ducts-but not to yo ur facebl e. T he TPS is supposed to signa l
blow ing, opera te th e blower sw itc h
that's an a ir-d istributio n problem. Air
"ki ll the alc " o n full thro ttl e to proa nd see if th e a irflow picks up . A nondistributio n is controlled by operating
vide improved pass ing performance,
running bl ower fan a nd a slow-runflap doors inside the hea ter/a ir-condibut the sen sor ma y come in w ith thi s
ning blower motor are purely electritioning case, a nd it's done either by vacsigna l when yo u're just bare ly touchca l problems, and are as likely to be
uum or electricity. H it's vac uum-operin g the gas peda l. Or if the a ir-cond irespo nsible for poor system perfora ted, look for a leak. tI

".>,c.";"">""""'«l\>_'".'",~<.,,,, ", , , , ,., ,_, , .,"

SERVICING YOUR A I C

47

EASY

Maintaining Your Battery

~II I "I I I I I

t's th e second time this week that
you've had to jumpstart yo ur ca r.
Bad eno ugh first thing in th e
morning, when you can use the battery in yo ur RV to give you a startbut standing in a rainy Wal-Mart
parking lot w ith yo ur hood open and
jumper ca bles in yo ur drippin g hands
is just plain humiliating, not to mention uncomfortable and inconvenient.
The standard solution: Install a
new battery- which mean s cough ing
up enou gh mon ey to bu y a new one
and have it installed.
A few minutes of attention once or
twice a yea r can perh a ps do ubl e the
life of yo ur battery, sav ing yo u co ld ,
ha rd cash. And, just as importantl y,
keep rain from running down your
neck in shopping mall parking lots on
storm y nights.

I

48

(Fig. 1) Always remove the
negative connection from a
battery first and reconnect it
last to prevent shorting the
wrench out on nearby metal
objects.

Would You Like
Fries With That, Sir?
First, you need to determine if yo ur
battery is indeed fried or not. Other
reasons for a no-start or barely start
cond iti on include, for openers, a marginal starter motor and high- res istance
wiring in th e primary (starter motor)
CirCU It.
Open the hood. If your top-post
battery terminals are covered with
green fur that looks like it belongs in a
bad sci-Ii mo vie, yo u'll need to cl ean
that up'. Start by pouring some wa rm
water over the terminals to di ssolve
the sulfation. Thi s accretio n is normal,
but it can prevent good contact
between the battery posts and the
clamp, w hich in turn keeps your battery from providing enough vo ltage to
start or prevents it from charging

properly. Remove the terminals, and brighten up all the
metal with a wire brush-style
battery post termina l cleaner
and a baking soda paste.
Don't splas h li quid around
the engine compartment or
onto the paint, and rinse
everything off thoroughl y.
Side-terminal batteries rarely
look worse than dull, but
that's eno ugh to ca use hard
starting. Wire-bru sh the contact surfaces to brighten them.
(See page 80.)
Dirt on the top and sides
of th e battery, even greasy
dirt, can hold enough moisture to crea te a current lea k
from the positive terminal
d irectl y to the nega ti ve termina
' making yo ur batter y selfdischarge more rapidly. Lea ve the battery clea n and dry.
Now take a close look at the terminal clamps on the cables. If they're
eroded too badly to provide good
mechanical contact, replace them.
Warnin g: Wh en eve r you work
o n a car battery, a lways di sconnect
th e nega ti ve terminal fir st-not the
p os itive (Fig. 1) . Wh y, yo u ma y ask?
Simple: If yo u accidentall y brush up
against the fen derwell or any o ther
grounded metal part of the car
w hil e you ' re unho o king the gro und
sid e, n o thing wi ll happ en. But if th e
gro und is still connected, and yo u're
wre nching o n th e positi ve sid e and
ha ppen to touch any metal, yo u' ll
be holding onto a wrench th at's sud denl y conducting severa l hundred
amperes . That's as much current as

MAINTENANCE

BASICS

than a single wire. Yo u have a cho ice
here. The best solutio n is to go to the
dea ler a nd get the co rrect p iece. T hat
may be inconvenient, a nd w ill ce rtain ly be expensive. Also (see page
89) , yo u may be able to get (at an
a uto parts store) a "ca ble repair sectio n" (termina l attac hed to a sectio n
of ca ble) . It's designed to attach to
cab le ends from which the battery
connecti ons a nd extra w ires have
been amputated . Or yo u can so lder
lugs of the appropriate size and ga uge
to the extra wires, and then attach the
lu gs to the clamp eit her by mea ns of
the cl amp bolt or a large sheetmetal
screw into the clamp body. Look for a
cl a mp w ith an extra terminal if thi s is
necessary, a lthough if yo u've got sideterm inal batteries this might be
impossible. As a las t resort, sp lice and
so lder the cab les together ahead of the
terminal. Be sure to use shrink tu bing
to cover the splice, espec ially if you ' re
sp licing the positive side.
W hen yo u rein sta ll the cl a mps,
co ver a ll exposed meta l with petrole um jelly, w hite grease o r m y own
persona l favorite, Cop-Graf or NevrSeez brand antiseize compo und. This
wi ll delay the inevita ble growth of
sulfur sa lts on the term inals by keeping mo isture from co llecting on the
ba re meta I.

HOW IT WORKS

Maintenance-Free Batteries
Like many things in life,
the term " maintenancefree" is only partially true.
Lead-acid batteries normally consume some of
the water in their dilute
sulfuric acid electrolyte
during a normal chargedischarge cycle. It actually
electrolyzes into hydrogen
and oxygen and escapes
as gas. So adding water
periodically is necessary
to keep the plates flooded,
although it can 't be done
Maintenance-free batteries often can have
on some batteries. (See
their lives extended by proper attention to
page 50) Maintenanceelectrolyte level and good connections.
free batteries use a cal cium alloy of lead instead
of an antimony alloy, which reduces
mal service life there should be no
need to add water.
the amount of electrolysis. In addition, the amount of free-standing
Any abnormal electrical system
elect rolyte above the plates is
condition or high ambient tempdesigned to be much higher in a
eratures may boil off more than
new ma intenance-free battery. This
the normal amount of water, however. Adding water where possible
means that there 's enough electrolyte to keep the plates covered
may extend the service life of
even after a few seasons of normal
these supposedly maintenanceuse. So, during the battery's norfree batteries.

a n arc we ld er- w h ich mea ns a large
sp ark , lo ts of hea t a nd eno ugh
energy relea se d to turn yo ur wrench
cherr y red w it h in a fe w seco nd s.
Avo id quicki e afterm a rk et unive rsal clamps that simp ly let yo u saw off
the o ld clamp and clamp o n the new
o ne. Wh il e these have their uses (kee p
one in yo ur on-ca r too lbox as a gethom e-to n ight exped ient) they ' ll
develop co rros io n betwee n the cla mp
and the cab le in a few mont hs and
leave yo u stra nded , again . If you feel
up to it and have a soldering iron
(proba bl y p ro p ane-fired ) ca pa bl e of
genera tin g eno ugh hea t, yo u ca n so lder a new cl a mp o nto th e existing
cable. Use ros in-co re elec trica l solder,
no t p lu mb ing so lder.
D on 't have th e Great M other of
All So lder ing Iro ns? The simple way
o ut is to rep lace the enti re ca ble. If

MAINTAINING YOUR BATTERY

yo u' re luck y, yo u can p ick up an
approp ri ate ca ble at the a uto p a rts
co unter. Genera ll y, all they stock a re
simp le one- lead cables, in positive a nd
gro und . Yes, there is a significant difference between the term inals
o n th e battery, and you rea ll y
o ught to use a black-insulated
ca ble on the gro und and a
red-in sulated ca ble on the
p os iti ve or the p ost w ill fit the
clamp poorly, w hich is how
yo u got into thi s mess in the
first place.
Unfortuna tely, it's no t
a lways that simp le. So me battery cla mps, bo th p ositi ve and
nega tive, are so ldered to mo re
(Fig. 2) A built-in hydrometer eye is a good check,
but won 't necessarily find
a bad battery.

All Hooked Up
You've eli mina ted battery ca bles and
clamps as the cause of yo ur no-start or
almost-start problem . And you figure

CHARGED

DISCHARGED

LOW
ELECTROLYTE

49

it's not a problem with
guised unde r a label
(Fig. 4) .
the starter motor, because
a jumpstart instantly
Open it up and look
brings the engine
insid e. The electrolyte
whirring to life. So far, so
shou ld come up to the
good. Maybe it really is
bottom of the filler cap,
the ba ttery.
or at least near it. If the
Does the battery have
level is down, especially
a built-in hydrometer
if the plates are exposed,
eye (Fig. 2) ? This eye
add water. Always use
has a small plastic ball
distilled water in a batsuspended at the bottom
tery. There is never any
of a clear plastic winneed to add additiona l
dow. The ball floats
electrolyte. Batteries will
when the battery is
normally consume water,
charged, turning the
but the sulfuric acid
window green. When the
component of the elecbattery is discharged, the
trolyte remains behind
ball sinks and turns the
and never needs to be
(Fig. 3) A proper batwindow yellow. If the
replenished.
tery hydrometer can
level of electrolyte is
Before you add
detect an underbelow the hydrometer,
any
water, suck
charged battery, as
then the battery is past
enough elecwell as pinpoint a
single bad cell.
its useful life.
trolyte out of
One danger of these
one cell into the
built-in bydrometers: They check only
hydrometer to float the bulb.
one of the six cells. If you've got a bad
Write down the rea ding.
cell (tbe normal failure mode for batSquirt the liquid back and
teries ), there's only one chance in six
repeat with the next cell. All
you'll know it from the hydrometer.
six cells should have readings
that agree within 0.050, or
A better check is to use a handheld
hydrometer (Fig. 3) . First yo u'll need
you've got a bad cell. These
to remove the filler caps. Battery clean? readings are temperature sensitive, so if it's very co ld or hot
Cover the battery with a rag and pry
o ut, yo u may need to correct
the caps up. Warning! Battery acid will
the readings. The hydrometer
remove paint, corrode electrical consca le eq uates the specific gravnections and potentially destroy your
ity of the electrolyte with the
eyesight. Wear eye protection.
state of charge of the battery.
First hitch: no battery caps to
If all the readings agree, and the
remove, it's a sealed, maintenance-free
gravity is low, the battery needs
battery. Maybe so, but there 's access
to be charged.
to the individual cells, perhaps dis(Fig. 4) Battery filler
caps may be concealed under a tab,
a pry-up cover, or
even under a large
vinyl label.

50

Charge
An alternative to the hydrometer test
(and one used by professionals): With
the battery charged, open circuit voltage
should be 12.6 to 12.8 volts with the
engine off and all loads off. With the car
running and all loads off, the voltage
should be between 13.6 and 14.5 volts.
Disable the engine by pulling the
fue l pump fuse. Measure the battery
vo ltage whi le cranking the engine. It
should read at least 9.5 to 10 volts
while cranking.
If the charging voltage is low, suspect some charging system problem.
But if the charging voltage is correct
and the cranking voltage is low, then
the ba ttery is suspect, as you've
already troubl eshot the wiring from
the battery to the starter and gro und.

(Fig. 5) Battery hold-down clamps are
essential to prevent a battery from
becoming ballistic.

Strapping In
Replacing the battery is straightforward . It's vital that the hold-down
clamps be reinstalled properly (Fig. 5) .
Some batteries use a wedge/lip
arrangement at the bottom of the battery, while others (usua lly in o ld er
cars) use a pair of long bolts and a
frame or lip to hold the battery down
to the tray. A battery is perfectly capable of holing a radia tor or smashing
expensive fuel-inj ection components if
it doesn't stay put. t;

MAINTENANCE

BASICS

EASY

Replacing a Battery
" H oney! T here's a woodpecker in the car!" she says.
It's too ea rl y in the morn ing
for this, and far toO cold for woodpeckers anyway. Yo u politely suggest
to your wife that she do two things
im mediately: Let you go back to sleep,
and let the woodpecker fl yaway in his
own good time. No luck, the kids
have to go to hockey practice-now.
As you stumble o uts ide, you rea lize the absurdity of it all. Now, you
know that there is no woodpecker in
your car, or an yw here nearby. The
pecking sound your significant other
has identified as avian in origin is
really just your starter soleno id clacking away merrily as she tries to start
th e car. Sleepily, yo u jumpstart the
reca lcitrant conveyance, and then try
to gra b another 40 winks . After
hockey practice, yo u' ll have to find
out why your night's rest was suddenly abbreviated .

(Fig 2) Use a battery cutoff switch to
diagnose parasitic current drains.

FLOATING
BALLS

Time Is On Our Side
The useful life span of an average
automotive batter y is four to seven
yea rs. With th e a uto companies'
eterna l quest to make cars and
trucks more efficient, two things
have consp ir ed to shorten this life
span: smaller batteries and h igher
under h ood temperatures. Higher
temperatures are so dam aging that
many cars have insu lating b lankets
for t he battery, or t he battery is
mounted in the trunk.
A single instance of deep-discharging a battery can reduce its life span
by half, so avoid running a battery
into deep discharge. If you do, then
charge it properly as soon as possibl e
before the plates inside bu ild up a
layer of sulfates. A properly charged
battery won't freeze, but a d ischarged
battery wi ll freeze at temperatures
well abo ve zero. Any battery that's
been fro zen is finished.

REPLACING A

BATTERY

(Fig. 1) This battery hydrometer shows
a fully discharged cell.

How Can You Tell?
Is one cell of the battery visibly different than the others? Look through the
side of a transluce nt-cased battery. If
one cell has substantia ll y less electrolyte
than the rest, or if one cell's lead p lates
are much lighter in color, then tha t cell
has gone bad and the battery is junk.
Charge the battery for an appropriate
time (depending on how powerful yo ur
ba ttery charger is) a nd then use a
hydro meter (Fig 1) to measure the specifi c gravity of the electro lyte. The more
charge on the battery, the more su lfuric
acid there is in the electrolyte and the
higher the hydrometer floa t wi ll be on
the scale. A battery tha t shows a low
state of charge on the hydrometer after

a long charge is dead. Don't rush to
judgment, however, because a deep ly
discharged battery will take a charge
very slowly at first.
Is there some parasitic drain in your
vehicle that's discharging your battery ?
An easy way to check is to temporarily
install a battery cutoff switch (Fig 2) in
the ground side . With everyth ing in the
car shut off, put an ammeter across the
switch, turn the sw itch off, wait at
least one hour, and measure the current drain. Up to 40 mill iamperes (ma)
is normal to keep the vehicle computers, rad io presets and clock alive. Anything more than 200 ma will run yo ur
battery down in a few days .

Transplant
Once you've determined the battery is
bad and the charging system and the
rest of the electrica l system is good,
it's time to install a new battery. Start
by rinsing the bad battery and the surrounding area with p lenty of water.
Th is wi ll wa sh away any sp lattered
battery acid, which otherwise would
eat through sheetmeta l, electrica l
wiring and the seat of yo ur britches.
Try not to splash it around.
Next, disconnect the battery's neg-

51

ative termin a l. If yo u accid enta lly
to uch yo ur wrench to anything
nearb y, no bi g dea l. Th en, yo u ca n
unhook the positive sid e. If yo u tr y to
un hoo k the positive side first, any
random contact w ith nearb y meta l,
such as the inner fender, will res ult in
a welder-like shower of sparks a nd
hea t. Remov ing th e ground side first
brea ks the circuit and preve nts this.
Side-terminal ba ttery hardwa re is
notori o us fo r not wanting to turn . Try
tapping ligh tl y with a hammer, and
rotating the w ire terminal slightl y as
you turn the wrench . Top-post battery
term ina ls are sometimes very diffic ul t
to re lease. Light tapp ing ma y help,
but yo u stand the chance of brea king
th e pos t off if you app ly any substanti a l force. Yo u may need to use a ba ttery post too l to elevate the clamp
loose from the post.

cla mps should not be defo rmed. Light
co rrosion can be wire-brushed off,
a nd a pas te of baking soda will help
neutrali ze any acid. R inse thoro ughl y.
If the attachment point of the wire to
the metal clamp is good, fin e. If the
cl amp o r the connection is nasty-lookin g, you sho uld replace the cable.
Reserve the cl amp-on, universa l cableend termi na ls for emergencies-th ey
wo n't las t as long as a proper connection and ma y contribute to yet
another premature battery failure.
Remember that the positive and negative posts on top-post batteries are
phys ically, as well as electr ically, diffe rent. Don't interch ange. You may be
a ble to rehabil itate an otherwise good
term ina l clamp by rep lacing the boltbut be sure to use a lead-p lated ba ttery
termina l bolt, not just something left
over fro m insta ll ing your screen door.

Nurse! Clamp!

How Dry I Am

Now's the time to ser iously eva luate
all of the wiring and clamps. T his
hardwa re carries substa nti al am o unts
of current- hundreds of amps for
short periods when starting the car,
and dozens for longer periods when
the engine is running. It's imperative
that it a ll be in good shape. T he

Most conventiona l batteries are
shipped with o ut any electro lyte in
them. If yo u have a good auto parts
store, they'll keep a supply of ready-touse batteries in assorted sizes on hand .
If not, yo u'll have to have one fi lled
and charged. Here's the procedure: Fill
the dry battery with electrolyte of the

correct specific gravity. Any place that
can sell yo u a battery wi ll have this.
Fill to the bottom of the filler neck, no
higher. Now wa it severa l ho urs while
the electrolyte seeps into the spongy
lea d plates . T he level will go down, but
as long as it covers all of the plates
inside yo u can proceed to charging the
battery. At this point th e battery p ro bably will start the car- but it's important
(Fig 3) A proper battery holddown is necessary for safety and long battery life.

HOW IT WORKS

Built-In Battery Test Windows

GREEN DOT
VISIBLE
(OK)

DARK
GREEN DOT
NOT VISIBLE
(CHARGE
BEFORE
TESTING)

LIGHT OR
YELLOW
(REPLACE
BATTERy)

Many maintenance-free batteries
have no access to the electrolyte to
check the level or state of charge.
But many of them have a built-in

TOP OF
BATTERY
GREEN
BALL

tester. This is a Plexiglas wand that
sticks down into the battery just
below the normal level of the electrolyte. At the bottom of this is a

small chamber containing a
loose plastic ball that floats in
the dense electrolyte when the
battery is charged. When it's
floating, you can see the green
ball at the top window through
the Plexiglas. When the battery
is discharged, the ball sinks and
all you can see is the dark electrolyte. But when the electrolyte
is too low, the plastic wand 's
bottom isn't submerged in it,
and you 'll notice a light color
through the window. This means
it's time to replace the battery.
Remember, this tester sees into only
one cell-there are five others, any
one of which could be faulty.

MAINTENANCE

52

BASICS

(Fig 4) Always reattach the battery 's
negative H terminal last.
that it be fast-charged fo r an ho ur or
so. Thi s mea ns being charged a t a
higher current than yo ur 4 -a mp ho usehold cha rge r ca n mu stel; so it must be
don e w ith at least 1 Y2 ho urs of super
highway cruis ing, or by a shop w ith a
fast charger capable of putting our 20
amps or so. Failing to do so will
shorten the battery's life spa n and
reduce its capacity. Now top up the
electrolyte, a nd rinse we ll .

Dropping It In
You've got the correct battery, right?
Check that the positive and negative
termin a ls are o n the proper sides, and
that the ho lddown clamp is the correct style. You may as well fa sten the

REPLACING

A

(Fig 5) Side-terminal battery posts are
easy to overtighten-be careful.
holddown first (Fig 3) . Use some a ntiseize compo und on the hardware in
case yo u ever need to rem ove the battery in the future. Don 't skip this step
beca use vibration w ill shorten the

battery 's li fe by crack ing th e delicate
lead p lates away from the internal bu s
bars. The worst case would be the
ba ttery shooting out of the tra y as
yo u bottom out in some p o tho le.
ow hook up th e positive terminal.
Wh en it's tight, put o n the red rubber
cove r. Now hoo k up the nega tive
(grou nd ) side (Fig 4) . Side-terminal
ba tteries (Fig 5) have a very sma ll bo lt
head for a reason. It's to keep overenthusiastic mechanics from overtightening th em and stripp ing the threa ds o ut
of th e so ft lea d terminal. Use a sho rt
wre nch to keep torq ue down.
Now cover the terminals with
p etrol eum jell y. This wi ll substantia lly
slow down the buildup of corros ion
o n the terminals. Finall y, be sure to
replace the battery heat insula tor if
th ere was one in stall ed. tj

BATTERY

53

MODERATE

Maintaining and Repairing
Your Suspension

'~----~~~!

"I

t feels like driving a truck,"
co mplallls your slglllficant
other. Okay, she was the
inspiration for " The Princess and the
Pea," and yo u point out, "Well, it is a
truck." Bur you know th e truth: It
used to ride and dri ve a lot more like
a car, a nd that's why yo u bought it.
T he ca rlike fee l of tod ay's p ick ups
and sport utility vehicles is th ere
w hen they're new. Bur most pickups
a nd some 5UVs have so li d axles (a t
the rear a nd even the front of some

54

~

-~---------------

four-wheel -d rive mo dels), and rear
suspensions with leaf springs. The
tuning is carefully balanced betwee n
an accep ta ble ride a t no load
(besides passengers) and something
to lerable w hen th e pickup bed is
stacked high w ith 2 x 4s, pan eli ng
a nd decorative brick .
50 it doesn 't take a lot of deterioration to make the ride/drive experience
something that even yo u have to
admit is somewhat harsh.
You can get all kinds of assist

(Fig. 1) Raise the vehicle on safety
stands. Then support the axle itself to
get the tension off the spring. Remove
the center U-bolt nuts, washers, plate
and then the U-bolts.

spr ings for the rear axle, including
aux ili ary leaves- even air assists th at
yo u can deflate or inflate. But the
object of th ese is to increase the load carrying capacity of the vehicle.
What you want to do is restore the
r ide/hand ling of everyday or weekend

MAINTENANCE BASICS

trips after 20,000 to 30,000 miles or
so have precipi tated a harsher ride
and vag uer hand li ng. There are aftermarket shock absorbers made for
p ickups and SUVs used primarily as
transportation, and they wi ll help. If
yo u want more, there are add itio nal
steps you can take to furt her restore
the r ide and ha ndlin g.

(Fig. 2) Removing
some spring
shackles can be
tedious, requiring
two wrenches.

()

()

Springs and Shackles
Look at t he leaf spri ngs-at the rear
on eac h side, even at the front if
yo ur ve hicl e a lso h as them there .
Loose center U-bolts are an occa siona l prob lem, and retighten ing
wit h a torqu e wrench co uld be helpfu l. But wh en the ride qua li ty is
down sign ifica ntl y, look closely for a
crack ed leaf (Fig. 1) , and if yo u find
o ne, c hange the spr in g, plu s the
mountin g bush ings an d shackle in
back . In fact, even w ith the leaves
intact, there can be eno ug h deteriorat ion in the rear shack les to justify
rep lac in g bot h for a rea l ride
im prove men t.
Take out the bolts t hat ho ld t he
spring assemb ly a t front and rear,

w hi ch ca n be easier said th a n done in
many cases . Turning the bolts while
hold ing the nuts with a second wrench
is straightforward stuff (Fig. 2) , but
the rear bo lts ca n almost "ma te" w ith
the rubber bushings inside the
shack le, a nd getting them out ca n be a
ted ious job if that happens. You may
have to slowly unthread the bolt,

w hi le at the sa m e t ime prying under
the bolt head to keep o utward pressure on the bolt. Or yo u m ay be able
to tap it o ut w ith a ha mmer and
punch. Just keep clear of the top of
t he end of the leaf spring, w hich co uld
snap up (aga inst the fram e) if there's
still some tension on the spring.
On some trucks, the shackle's upper

HOW IT WORKS

The Leaf Spring Suspension
The leaf spring suspension is a popular
choice for the rear of trucks and some
sport utility vehicles. It has been used
for some heavy-duty truck front suspensions and the rear of passenger
cars, but the leading application is the
truck/SUV with the nonindependent
rear axle. The leaf spring has several
leaves-simply adding leaves
increases the load-carrying ability of
the suspension. The top leaf typically is
the longest and each end of that leaf is
formed into an eye, into which a rubber
bushing is installed. The spring eyes
are bolted to the chassis in front and
attached at the rear through a hinge
joint called a shackle. The shackle permits the spring to
effectively change its length as it flexes to absorb
impacts. The leaf spring also attaches (through U-bolts)
to the solid rear axle, so it locates the axle without the
use of arms, an important function. This permits a simple

MAINTAINING AND

REPAIRING

YOUR

SUSPENSION

suspension design with obvious packaging benefits. However, these advantages are offset in passenger cars and
some SUVs by the superior ride qualities of the coil
spring, which merely supports the vehicle and simply
compresses and expands as it absorbs the impacts.

55

the y' re bad ly cracked, p erh aps mi ssing chunks of rubber, insta llin g
rep lace ments will help elimin ate bod y
shake. Occasiona lly, the meta l fl oor
pan of the vehicle is the problem- it's
ru sted and weak . A piece of ga lva nized fl at sheetmeta l, thick en o ugh for
support, sho uld be welded in place.
Even if yo u just have to replace
bad bushings, don't simply loosen the
bolts and pry to get clea ra nce to
in stall replacements, or yo u co uld
ca use damage you won't see. Thi s
work normally requires loosening
radiator mo unts, the steering gear and
col umn, and other parts, so check and
fo ll ow the fa ctory-prescribed procedure for yo ur ve hicle. Or better still,
lube periodically and the bu shings
will be fin e.
(Fig. 3) Check frame-to-body and
suspension bushings. Look for cracks
or overly brittle rubber as well as missing chunks.

bo lt is in sta lled o n the inboard side
a nd it won 't cl ear the frame to co me
o ut. Jack up the rear of the ve hicl e
until the shackl e end of the leaf
spr ing comes down far enough below
the frame.
The origina l equipment bushings
with those meta l shack les are part of
th e reaso n for loss of ride qua lity. To
get a long-term smoother rid e, in stall
aftermarket shackles th at include
sma ll rubber springs with two m eta l

sleeve inserts and meta l arms-a lmost
a reverse of th e origina l equipment
design. The Dana Ve lvet-Ride series
that we in stalled is an example. You
a ttach the meta l arms to one meta l
sleeve of the rubber sha ckle, insert
and tighten th e through bo lt and nut,
a nd then install the new sh ack le in
place of the original. The meta l arms
connect to th e chassis and the rubber
spring, and the rubber spring is bolted
(through its second metal sleeve) to
th e leaf spr ing.
In spect the underbody fram e-tobody bushings (Fig. 3) a nd the radius
rod bu shings, and apply rubber
lubricant as routine maintena nce. If

Steering Stabilizers
Is a lot of vibration coming through
th e steering wheel? The pro blem
cou ld be w heel ba lance or a lignment,
even the stee ring gea r's free play
ad justment. But if it's a low-speed
problem on second a ry roads, look for
so mething worn o ut.
If yo ur operation has pounded the
tightness our of steering p arts, yo u
ca n feel the looseness wh en yo u grab
(Fig. 4 ) Shimmy can be caused by a
worn or loose steering stabilize r. Check
t he mounts, and check the damper for
a bent rod or leakage.

........

.

:.::: .. : . . .. . . .
.

~

."

. ..

: .. .- . : ....... . .

.' .
:.....

MAI N TENANCE

56

~

BASICS

the tie rod and idler arms and find
yo u ca n flex th em too eas il y. If yo u
want to rep lace them just this
o nce, get heavy-duty parts specifica ll y des igned for pick ups a nd
SUVs. They' ll not on ly be labeled
for heavy-duty use, but they' ll have
grease fittings, which th e origina l
equipment may not.
Man y vehicles have steeri ng
sta bili zers . If the ve hicle is suffering
from vibration and shimm y, look
for worn-out stabilizers, bas ica ll y
one or two horizonta lly installed
" dampers" (shock absorbers) that
connect the steering linkage to the
frame or axle (Fig. 4) .
The dampers mount to the
steeri ng lin kage with a bracket
(held by U-bo lts) and to the fram e
or fro nt axle w ith ano ther bracket,
and there are washers and rubber
bushings at each end. If they' re
loose but the bushings look good,
a simp le tightening ma y remedy
the probl em. When they have significant mil eage on them , repl ace th e
dampers along with mo unting hardwa re and bushings.
If you don't have stabili zers, but
use the vehicle on bad roads a lot a nd
want to get rid of the shimmy, there
are kits yo u can install, complete with
fra me brackets and U-bo lts. These
kits have been a fac tory fi x for otherwise unfi xa ble shimm y for yea rs, and
aftermarket kits for trucks and SUVs
are avai lable.

Jounce Bumpers
Have th e rear axle jo unce bumpers
been taking a beating? If the y have,
yo u may see that the ends are sc uffed.

MAINTAINING AND

REPAIRING YOUR

However, yo u proba bl y know witho ut even look ing wh ether o r no t th e
vehicle has been botto min g. If yo u
get stiffer shocks, yo ur norma l rid e
will suffer. A better approach is to
replace the jounce bumpers w ith
ones that rea lly are sma ll rubber
assist spr in gs, such as Mo nroe 's
Muscle LSE . They look lik e a short
stack of thick pan ca kes, a nd when
yo u're dri ving on bad roads they
make co ntact w ith the jo unce pad on
the ax le a nd prevent bottoming o ut.
You could perceive this as causing a
slight stiffening of the ride, but the
bottoms of the "s hort stacks" have a
co upl e of inches of clea ra nce to the
pads, so they're o nl y in the p icture

SUSPENSION

on bumps . And because they 're
springs, they a bsorb impact so th e
overa ll rid e qu a lity sho uld be better.
On man y trucks, yo u can just
unbolt the bracket that holds the o ri ginal jounce bumper, bolt on a universal bracket (with elo ngated holes) a nd
attac h the "short stack. " If the jo un ce
bumper bracket is riveted to the
frame , use a chisel or han d grind er to
cut it loose.
After installing the bracket and
rubber spr ing, tighten the bracket
bolts lightl y, then lower the vehicle to
the gro und, adjust the bracket height
to the reco mmend ed cl earance w ith a
normal load in the truck bed, a nd do
a fin a l tightening. t6

57

DIFFICULT

Replacing Shock Absorbers

o ur wife has started to so und
li ke a detergent commerc ial,
bragging about the spilled coffee stains she's gotten out of yo ur
shirts. The kids are making excuses
about why they'd rather ride their
bikes to the mall than get a lift in your
car, and even the dog has started to
get carsick. Wake up, Bunky, and realize that your vehicle's ride has gone,
litera lly and figuratively, downhill.
Hey, there are over 60,000 miles on
the odometer, and the tires are starting to develop little concave "cups,"

Y

58

sure signs it's time for new shocks.
Of course, yo u co uld get the
jouncy ride of worn shocks at much
lower mileage, perhaps because you
drive briskly on bad roads and accelerate the wearing-out process. Or
may be the shock mountings have
loosened . Occasio nally, a shock produces a visib le leak of fluid, but some
hint of weep is normal, and most
shocks we've seen that were well
worn o ut, also looked bone dry.
That's right, we're talking about
shock absor bers . The MacPherson

(Fig. 1) Removing shocks is usually
straightforward, but getting under the
vehicle and applying sufficient torque
to remove large-diameter rusted-on
fasteners can be daunting.

strut is in wide use, but conventional
shocks are on lots of cars, plus almost
all those SUVs, pickups and at least
the rear suspension of minivans. Isn't
replacing them just like changing
struts, just easier because yo u don't
have to compress and remove the co il
spring? No, although some things are

MAINTENANCE

BASICS

simil a r (a st rut is rea ll y a
type of shock abso rbe r),
th e mo unti ngs-a nd th e refo re th e rep lacement procedure- a re different.

o bvio usly cracked o r ba d ly
di sto rted, yo u' ll usua ll y
have to rep lace th e shoc ks
to get the new bu shings.
T ha t's o kay, beca use th e
shocks themsel ves don 't
fi gure to be in much better
shape.

Those Mountings
Both shock mo untings o n
most la te-mo del ve hi c les
a re in the un derbody, so if
yo u support th e c hass is o n
safety stands, yo u have
access to the top a nd botto m. O ne proble m is
rea ching them . A noth er is
gettin g o ff th e h a rd wa re

Replacement
Shocks

Th e afterma rk et m an ufacturers produ ce repl ace ment
ARM
shocks fo r just about
everything, except som e
(Fig. 2) If the shock rod spins endlessly as you try to remove
electroni call y controlled
the upper mount, try Vise-Grips on the flatted end of the rod.
(Fig. 1) .
d es igns. On Iy a ha ndfu I of
T he first thing to d o is
electro n ic systems' shocks
see if th e mo untings are loose . If yo u
stud, so yo u ca n ho ld the stud w hil e
a re not a va ila ble fro m th i rd p a rti es,
ca n turn th e mounting nut or bo lt a t
yo u ti g hten the nut.
eith er beca use th ey're a n o ddba ll size
th e top or bo tto m without mu ch
or beca use th e ti e- in to the vehicl e
W hen a nut a nd bo lt loosen, yo u
effort, the mounting is loose . O n some
may be ab le to just retig hten. Howelectro nics wo uld result in a ride/
shocks there's a stud in a rubber bushever, it will loosen aga in if yo u do n't
ha ndling g litch if yo u in stalled noning, a nd if it tears loose, yo u' ll see a nd
a pply som e threa d-lockin g compo und
electro nic replacements. It mi ght be as
fee l it turn as yo u try to ti ghten the
to th e threads.
li ttle as a tro uble code or wa rnin g
nut. T here's typi ca ll y a hex o n the
If th e shock bu shin gs' rubb er is
li ght, but if th ere's ma jor integra ti o n,
UPPER
CONTROL

HOW IT WORKS

Shock Absorbers Don't Absorb Shocks
A shock absorber doesn't absorb shock (the spring does
that, by flexing to absorb the energy of an impact). The
shock absorber actually stops the vehicle from bouncing
up and down on the flexing spring. It does this by transferring the spring-flexing energy to a piston in an oil-filled

Single- and double-tube shocks are used on either the
front or rear end of most vehicles. Struts are simply a
shock that includes the spring perch and a bearing that
replaces the upper ball joint.

chamber, which dissipates it in the form of heat. Most
shocks have twin-tube (chamber) arrangements, an inner
chamber with the piston and a calibrated valve at the
bottom, which has the entry passage to an outer cham ber-the reservoir. When the piston comes down on compression, it forces fluid through the calibrated
valve into the reservoir. When the piston moves up
as the shock absorber extends, oil is drawn from
the reservoir into the main chamber, and some
also flows through orifices in the piston, as part of
the ride control calibration. A charge of low-pressure gas in the reservoir reduces oil foaming,
which would affect ride control. Many high-performance shocks, including some for heavy loads
such as motorhomes, are of single-tube construction, with a high-pressure gas charge in the base.
Fluid flow is between the areas below and above
the piston, which has a sophisticated valve
assembly. The higher pressure of the single-tube
design is even more effective against fluid aeration, but at the expense of ride comfort. Strut
replacement is sometimes a job for a pro with the
right tools and coil spring compressors.

l
REPLACING

SHOCK ABSORBERS

59

In most other cases, yo u
get a cho ice of shock
a bsorber designs.

Getting the
Shock Off
If th ere's an electrical

(Fig. 3) There are several special
tools available for holding the shock
rod, in an assortment of sizes, at
auto parts stores. Use a box-end
wrench to loosen the nut while you
hold the rod stationary.

it co uld be mo re th an th a t.
Just check th e manufacturer's catalog, a nd if there are shoc k a bso rbers
li sted for your exact year, ma ke and
mode l, and th e listing says it covers
th e electronic control system type, yo u' re cool. You
will be giving up the electronic co ntrol , but there
isn 't a system that's all th at
sophisticated o n anything
but a few premium cars,
such as Ca dillac, M ercedes, Co rvette and some
oth er high-end sports cars.
If th e afterm ark et catalog doesn 't Iist a rep lacement, yo u' re stuck with
ordering rep lacement
shocks from a dealer. On
so me Ford products there's
an external motor drive,
and yo u can unplug it
from the o ld shock and
in sta ll it o n th e new one.

(Fig. 4) Generally, a
socket will spin off the
mounting hardware. New
hardware is usually
included with the shock.

60

connector, sta rt by
unplugg ing it. No electron ics problem with
in sta llin g con ve ntion a l
shocks? You could
just cut the w iring,
and tape sec urely. But
if there's any chance you
or a subsequ ent owner
will want to re-estab li sh
th e system, th at wo n't wo rk.
If the co nn ector is in th e
trunk, th at's easy (just tape
over it). But if it's underneath, find a safe loca tion
away from exha ust hea t,
pack it with pieces of plastic foa m stuffed aga in st the
termin a ls, put it into a heavy p las tic
pouch, sea l a nd ho ld it in p lace with
a ca ble ti e.
Loosening a ru st-frozen nm a nd
bolt is o ne of th e ma jor headac hes in

shoc k replacement. If a nut is
exposed, yo u sho uld be ab le to
loose n it with a nut splitter, a c1 a mp lik e too l yo u o ften can rent from an
a uto p a rts store . No space for th e
splitter? Penetratin g solvent, followed by hea t from a torch, is
a nother possibility. The most diffi cu lt is th e type where the pi sto n rod
turn s w hen you try to loosen th e nut.
One app roac h is to clamp lock in g
p li ers onto th e " do ubl e- D " end of
th e piston rod, ho ld it fr o m turning
w ith the pliers and loosen the nm
w ith a conventional wrench (Fig. 2) .
So methin g better (pa rticul a rl y for
recessed insta ll ations) is a spec ia l
too lkit with a holl ow hex that fits
ove r th e rod o nto th e nut, followed
by a wre nch (made to fit th e do ubleD ) th a t goes through th e ho ll ow hex
onto th e doub le-D end (Fig. 3) . Inexp ensive kits, with three h ollow hexes
for most U.S. makes, or even so me
for spec ific models, a re r ea dil y ava il ab le in a uto p a rts sto res. It co mes
with three ho ll ow hexes for mos t
U.S. makes. Th ere's a lso o ne spec ifically for so me Ford products. If the
shock p isto n end (or stud en d ) has a
conventional hex, yo u can
use an ordinary socket, of
course (Fig. 4) .
Many shocks are
mo unted o n studs, and
we 've even seen those
wh ere th e shock upper
m o unt ha s a retaining
brac ket held by an additi o nal stud and bolt. It's
no t a ma jor difficult y, just
extra hardware to remove .
Wh en yo u get the nuts off
a stu d mo unting, yo u still
have to pry off the shock,
wo rking evenl y at top a nd
bottom so it doesn't cock.
If yo u' re not sure of th e
cond iti on of a bone-dry
shock, just disconnect it
from th e bottom mo unt if
possible (o r re move it com pl etely if it's o n studs).
Then slow ly co mpress th e
shock (even low-pressure
gas shocks will be eas il y

MAINTENANCE

BASICS

LOWER MOUNTING BOLT

(Fig. 5) Lower mounting bolts are usually, but not always, included in the new
shock's box.

compressed ). If you feel a ny lost
motion (" looseness" or unevenn ess),
th e shock is worn out.

Installing New Shocks
If yo u' re o n a budget a nd in sta lling
nongas shocks, it's a good idea to
m ake sure the y don 't h ave air inside
a nd bleed it o ut if th ey do. (Don't try
this o n o ld shocks. If the y have a ir
insid e, it's from internal wear, a nd
bleedin g is not a c ure.) W ith new no n-

REPLACING

SHOCK

ABSORBERS

gas shocks, bl eed by holdin g each
shock upright (in sta ll ed positi o n ):
Extend it, a nd th en turn it upsid e
down a nd co mpress . Repeat t he procedure a few tim es a nd th e new shoc k
sho ul d opera te smoot hl y, w ith somew hat grea ter resistance on extension .
Us ing adjustab le shocks? So me
ha ve soft, norm a l an d fir m p os iti o ns,
and a lth ough yo u ca n mak e ad justments after in sta ll a ti o n, sta rt with
so ft or nor ma l (firm is best fo r " rid e

restora tion " after tens of th o usa nd s
of mil es of use).
Th e mounts for rep lace ment shoc ks
often are very different from those for
th e origina ls. That's okay, so lo ng as
you follow the instructions carefull y.
A common exa mpl e is th e aftermarket
hardware for th e "stud-in-bushing"
design used o n ma ny Genera l Motors
ca rs. T here's a sp ecia ll y shaped stee l
rep lace ment stud assembly that goes
into the lower mou nting, an d th e
bushing that's in the rep lacement
shock just slides onto it (Fig. 5) .
If th e shock mounts on studs and
the nut is tough to threa d o n, clean
th e threa ds w ith a wire brush a nd
app ly penetrating o il/so lve nt. If the
nut a lm ost sp un off, apply a film of
threa d-locking compou nd to t he stud .
If yo u ca n ti g hten the shock hardware
to specs w ithout distorting the bu shin g, that's ideal. If the nut hits the end
o f the threa ds and th e bushings are
loose, yo u've got th e wrong o nes- or
yo u're mi ss in g so me hardware. ~

61

EASY

Maintaining Your Exhaust System
(Fig. 1) Tightening a loose clamp won't
help if the bracket has broken loose at
the weld line.

T

he sign says " DIP." And it's not
advertising a sa mba sch oo lthere's a dip in th e p a vement
la rge enough to lose a first-grader in.
Yo u to uch the brakes lightl y to keep
fro m spilling your ja va as yo u traverse
it. But there's a sudden graunching
no ise fr o m under yo ur car, fo ll o wed
by th e screa m as a bo ut a ga ll o n of
fast-food coffee £lenses the skin fr o m
yo ur thigh. You pull over to inspect
your leg and the underside of yo ur ca r,
in that order. There are big, hot
chunk s of metal hanging loose under
yo ur chass is, a nd th e exha ust system is
nea rl y d raggi ng.
Tod ay's exha ust systems co nsist of
a lo t o f expensive pa rts. Tb ere are
o ne o r mo re ca tal ys ts, a n oxygen sensor, ma ybe even a 2-stage muffler.
Th ere's piping tha t's not onl y shap ed
to cl ea r und erbod y lines, but a lso
may be m ade of premium meta ls, in
so me cases du a l-wa ll tu b ing. Th ere
a re sheetm eta l underbo d y bea t
shi elds to prevent tbe exha ust fr o m
igniting dry grass .
Wb a t's bolding everything
togetber? A few clamp joints a nd
so me weld s. Wha t's bolding every-

62

thing up? A few pi eces of rubber with
some brac kets. Wh a t's keeping everything aligned? Th ose sa me few pi eces
of rubber and brackets. Fa ilures are
common and they ra nge fr o m cracked
rubber to fail ed welds.
Before yo u suffer the sa me expensive fate we described ea rli er, ta ke
time to perfo rm a reg ul ar und erbod y
inspection-it's easy. To get started,
jack up the car a nd suppo rt it on
safety stands front a nd rear. No w
you 're read y for a n in -depth look.

Hangers
If a ny ha nger is bro ken, it has to be
re placed, w itb o ut delay- eve n if the
exha ust system seem s to be ha nging
level. One broken ha nger mea ns tba t
when the system mo ves up a nd down
as you dri ve, a whipl as h effect goes
through tbe cl amped a nd welded
joints. Eventu a ll y cl a m ps loosen a nd
welds crack.
Repl acing a broken ha nger used to
be simple, beca use most compa nies
used some type tb at bo lted to the
body and clamped to some p a rt of the
exhaust system. Today, the most p opular design uses rods welded to the

p ipes a nd, often, to the ve hicl e underbod y (Fig. 1) . T hese ha ngers a lso have
a thick rubber sectio n th at resembles a
fl attened foo tba ll or beacb ball , witb
bol es fo r a rod a t each apex of th e
rubber. Weldin g pos iti vely loca tes a ll
the pa rts, a nd a lth o ugh yo u may ha ve
to tug a nd pry, rep lacing the rubber
piece w hen it becomes crac ked is ve ry
stra igh tfor wa rd .
Yo u ca n in sta ll a bra nd-new p ipe
if t be ro d com es off the pipe, but if
th e pi pe itse lf is go od , tb a t's a n
unn ecessa rily to ugh a nd exp ens ive
r ep lace ment. The altern a tive is to
in sta ll a unive rsa l ha nger, th o ugh
thi s may require a bit of jury-ri ggin g.
First, rem o ve the bro ken ha nger.
Then loo k for a nearb y hole, perhaps
even fro m th e o ld ha nger. Ta ke a universa l ha nger tha t ca n tw ist a nd tilt
a nd has a n adju sta bl e length setup ,
a nd a ttac h it to th e und erbod y w ith a
bo lt (a nd if it isn 't threa ded, a lso
with a nut ) throu gh th a t hol e. Nex t,
ma ke th e co nnecti o n around tb e
pipe- a simpl e cl a mp a nd U-bo lt
usua ll y wo rk s (Fig. 2) . D o n't be surprise d if a pa rt of the welded-o n
brack et (fro m th e bro ken ha nger)
has to be c ut o r gro und o ff to provide space fo r th e cl a mp th a t w ill
a ttac h to th e uni ve rsa l ha nger. Yo u
sho uld tr y to ma ke a ttachm ents ver y
cl ose to th e loca ti o ns of the o ri gina l
equi pm ent se tup'. Thi s will m a inta in
system a li gnm ent a nd th e ba la nced
ha ng o f th e entire system .
If t here is no ise fro m exha ust
sys tem contact w ith th e underbod y o r
a n und er bod y pa rt, yo u sho uld c heck
fo r da mage undernea th. Exha ust system cl eara nces are limited , a nd if yo u
see th e need to increase o ne, it m ay
be p oss ibl e to bend or shim a n ori gi-

MAINTENANCE

BASICS

na l-equ ipm ent ha nger. If a rod -type
ha nger is we lded in p lace, see if yo u
ca n bend it w it h a p iece o f pipe over
the rod 's o pen end. If yo u need mo re
tha n Y< in . o r so, loo k fo r a n a ltern ati ve . If t he ha nger is a bo lt-o n to th e
bod y, for exa mp le, yo u m ay be a bl e
to insta ll was hers as shims.
So me o lde r impo rts have rub ber
ha ngers tha t rese mbl e thic k ru bber
ba nd s. If th e o ld ba nd has bro ken o ff,
yo u ca n get a replace ment, but
insta lling it is not a ma tter of simp ly
st retc hi ng it over t he retaining ta bs.
The ba nd is so t hi ck a nd stiff yo u
p ro ba bl y w ill ha ve to pry p rett y ha rd
to get it o n.
Ma ny ex ha ust systems have a
bracket to prov ide firm suppo rt cl ose
to th e tra nsm issio n. If the bracket
cracks- o r if it was removed for se rvice a nd never reinstalled-tha t ca n
acco unt fo r a lot of exha ust system
fl ex a nd event ua l crac king. If yo u
ca n't get a rep lace ment bracke t, yo u
may be a ble to get t he old crac ked
o ne rewe lded . Bu t replace ment is the
bes t cho ice, a nd if t he dea ler doesn 't

ha ve it, th e wrecki ng ya rd ma y.

Shields
Exha ust system hea t shi elds a re pro ne
to da mage fro m d riving o n ro ugh
roads. To a vo id th e possibility of a
g rass fi re, repl ace a ny t ha t are m iss ing
o r barely ha nging o n. If a shi eld is
dented , unbo lt it, a nd check the
ex ha ust syste m fo r da m age .

Exhaust Joints
If there has been a lot of exha ust system up-down travel beca use of a broken hanger, t he cl amps and joint may
be dam aged. If a welded jo int is
cracked a t a muffler o r resona to r jo int,
yo u ca n rep lace the pa rts. Or to save
mo ney, cut away the piping a nd pa rt of
the neck jo in t, t hen install a sho rt connecto r pipe a nd secure it w ith clam ps.
If a cl a mp ed joint isn 't cracked,
but is lea kin g exha ust gas, re m ove the
o ld cl a mp. If th e pipe ends a re badl y
d istorted , yo u' ll have to rent a p ipe
ex pa nder to res hape t hem . O th erw ise,
sepa ra te th e p ipes, sa nd th em to
remove a ny ru st, t hen a pp ly a coat o f

(Fig. 2) Sometimes a universal aftermarket clamp will fill the bill and let you
reattach the OEM hanger.

HOW IT WORKS

Muffler
A muffler is a canister
with internal tubular passages , shaped in part by
baffles, designed to
gradually reduce the pulsations of flowing
exhaust ga s. The slowdown creates back pressu re in the exhaust system , all the way back to
the engine itself. This
slows down the exit of
exhaust gas from the
engine, reducing its performance. To get around
this problem , many high-performance engines
increase the exhaust flow with larger mufflers and
accept some increase in exhaust system noise as a
result. With careful design, however, including the use
of silencing materials, the systems can be made to
meet legal restrictions. Some back pressure is benefi-

MA I NTAINING YOUR

EXHAUST SYSTEM

cial at low speed,
because slowing down
the flow pattern of intake
and exhaust gases
improves performance
somewhat. Many engines
have 2-stage mufflers
with an internal springloaded valve. These mufflers maintain a specified
amount of back pressure
for good low-speed performance. But when the
engine is at higher speed
and there's more exhaust
gas to flow through the muffler, back pressure builds
up. Before it can become excessive, it pushes open
the spring-loaded valve, and the gases take a far less
restrictive flow through the muffler. This "second
stage" permits the engine to develop considerably
greater horsepower at higher rpm.

63

p

(Fig. 3)
Springs on the
bolts at the joint at the
base of the headpipe allow the
exhaust system to flex slightly as the
engine moves on its mounts.
Replace broken or sacked-out
springs to prevent a leak.

ex ha ust pipe sea ler. Reassembl e a nd
insta ll a heavy-du ty cl a mp , which ca n
tol era te much more torqu e, to provide a leak-free joint.
Many sys te m s ha ve a flan ge jo int
at the exhaust manifold or at the
manifold 's Y-pipe. That joint is held
toge th e r w ith sprin g-load ed bo lts
(Fig . 3 ). T he hea t m ay weake n the
sprin gs, a nd th e jo int w ill loose n.
Tr y s impl y ti g htening the bo lts, b ut
if the springs ha ve cracked or are
weak, repl ace th e bolts . Th ey' r e
sold, with new springs, in auto
parts sto res .

64

If a flange joint is bad ly
ru sted, it's wo rth trying to free it
up w ith penetra ting so lve nt. Th en,
take it apart and see if it ca n be sa lvaged by sanding it clea n, installing a
new gasket with sea ler and rea ssembling with new bo lts a nd nuts (drill

o ut rusted stud s if necessa ry) . C heck
at a n a uto parts sto re to see if a
cl amp-over rep air fittin g is ava ila bl e.

Damper Weights
Some exha ust system s ha ve vibration
da mpers (Fig. 4) , which are weights
that are a ttached to a
pipe or a re part of a
fl ange co nn ecti on. If a
damper we ight brea ks off
or is bent, th e exhaust
system wi ll vibrate
noticea bly. This not only
makes for an uncomfortab le ride, but it can affec t
th e life o f we lded a nd
cl a mped joints. tj
(Fig. 4) When using
replacement parts, be
sure to reinstall any original vibration-damping
counterweights.

MAINTENANCE

BASICS

EASY

Replacing Your Belts

N

Ot aga in! You cra nk the car
through a turn and the steering
suddenl y gets almost rock hard .
Both yo ur heart and th e steeri ng wheel
seem to stop. As you apply more muscle
to the steering wheel, yo u hear sharp
squealing from under the hood. O n the
dash , the alternator warn ing light shines
brightl y. As your vita l signs normalize,
yo u remember that yo u've had this happen before: T he accessory drive belt for
the power-steering pump either is slipping badl y or has popped off.
Today 's drive belts, p articularly the
ribbed belts, are supposed to las t for
years. You even know peop le who've

REPLACING

YOUR

BELTS

neve r had to c hange them. Why do
yo u ha ve repea ted belt problems?
The answer is tha t something'S
wrong with yo ur belt's drive. Don 't just
put on a new belt, grumble and wait
for the next belt failure. Find o ut w hy
yo ur car has an appetite for drive belts.
T hen make a more durable repair.
First, inspec t a II of the bel ts a nd
each of the pulleys (Fig. 1 ). Twi st
over each belt and c hec k it thoro ughl y. O n a simp le V-belt, look at
th e sidewa lls, and if the y're glazed,
t hat's a sign of slippage- typically
caused by improper adju stment, but
poss ibly a sign of a bad pulley, too .

(Fig. 1) A belt that's installed improperly, or one riding on improperly aligned
pulleys, will not last long.

On a multi ribbed belt look carefu lly
for mi ss ing chunks of rubber. Specifically check for gaps at least a ha lfinch or longer on ad jacent ribs.
If the belt hasn't lasted long, the
reason w ill be found during in specti on of th e pu lleys. There are lots of
reasons why so me cars eat belts.

Feel The Tension
Most cars and trucks use a single, serpentine belt (see "How it Works,"

65

POWER STEERING
PUMP PULLEY

CORRECT
ROUTING

ALTERNATOR
PULLEY

(Fig. 2) Correct routing of serpentine belts is not easy, especially in
a crowded engine compartment.
Incorrect routings may almost fit,
so check the routing diagram or
the owner's manual.

page 68) to dri ve a lot of accessories.
These belts typica ll y are tensioned by
an idl er pulley with an automatic tensioner. Ju st becau se there's an au tomatic tensioner doesn 't mean it's
working right. Any of the root causes
discussed below can result in a belt
getting chewed up fa st, o r popping off
th e pull eys .
Th e re's a ten sio n indicator o n th e
idl er a nd it shou ld be reaso nab ly
c lose to midpoint. It shou ld not be
resting o n the stop ta b at the " loose"
end . If it is at the stop- or very
c lose-the belt ha s stretched and
sho uld be replaced before it pops off.
You just put in a new belt, yo u say?
Maybe yo u routed th e belt incorrectl y. Yes, it is poss ibl e to get th e
be lt wrapped arou nd all the pu ll eys
in w ha t seems to be the right way but
have it wrong . Check the belt- ro uting
diagram (Fig. 2) , which on many cars
is o n an und erhood la bel.

66

Are yo u sure yo u have the right
belt? Just because the tension indicator
is in the right place doesn't mean yo u
have th e correct belt. It's hard to eyeba ll th e difference between 7-rib and
8- rib belts, and if the pu ll eys have
more or fewer grooves, the belt won't
sit right. Even if th e number of
grooves matches, it's possibl e to insta ll
th e belt too far inboard. While yo u're
look ing at the tensioner, also check for
cracks in the housing w hi ch wou ld
a ll ow it to fle x enough for trouble.
Noth ing obviousl y wrong ye t? If
the belt is still on the pulleys, run the
engine and eyeball th e accessory drive.
If th e tensioner is vibrating a lo t but
the pulleys are running smoothl y, the
damper bL.lshing is bad a nd yo u' ll
have to install a new tensio ner.
Put a wrench on th e spring te nsion er (Fig. 3) . Usually there 's a
square hole for a ratc het or breaker
bar drive, and occasiona lI y yo u can
use o ne of those. If the tensioner on

yo ur transverse-engine car is buried
so deep down between the pulleys
and th e suspension tower that you
can bare ly see it, c heck o ut the
asso rtment of specia l long, thin
wrenc hes designed for those in stall ation s at yo ur loca l a uto parts store .
The lea ding m akers of th ese specia lty
too ls will have theirs o n display (Lisle
Too ls, K-D/Dannah er a nd Schley/SP).
With th e wrenc h o n th e tens ioner,
app ly so me lig ht torg ue in the disconnect direction, and if th e wrench
moves very easily a short distance
and th en gets stiff, th e tensioner
ho using spring eith er is out of position or broken. This co nditi on often
causes th e te nsio ner and its idl er p ulley to vibra te.
Not today? Keep app lyin g effort
w it h the wrenc h, a nd yo u sho uld feel
uniform spring ten sion a ll the way to
the belt-off position. If yo u feel bindin g or lost motion at a ny point,

MAINTENANCE

BASICS

a noth e r o ne, howeve r, t he
o n ly fix is to shim o ut th e
accesso r y w ith was he rs,
w hi c h is a b it o f c ut-a nd -try.
Do some to uchy-fee ly o n
th e idler p ull ey. Try to turn it,
a nd if it's se ized, the tensio ner
has to go . jf it turns, fee l fo r
roughness (w hi ch in d ica tes a
ba d bea rin g) a nd if yo u come
up w ith a da b o f grease from
th e bearing a rea , th a t indi ca tes a grease leak past a bad
sea l. Try to rock th e pull ey :
In -a nd-o ut m ovement m ay be
TENSIONER
a sign of a loose bolt, but
Playing With Pulleys
'"
mo re lik ely a da maged p ull ey.
If t here's wo bbl e in th e idl er
If a pu ll ey is stee l and it's
o r a n yo ne of th e o th er accescl ea rl y rusted , th a t not o nl y
so ry pu ll eys, th e pulley co ul d
indicates t he coa tin g has
be cracked or worn loose .
wo rn o ff (no rm a l, in tim e),
Just o ne da m aged pull ey a nybut tha t it is da maging th e
where in the accessory drive
(Fig. 3) Most automatic tensioners provide a square hole
und erside of the belt a nd yo u
also ca n affect th e o peratin g
for a 'h-in. ratchet.
have to rep lace it.
appeara nce of th e tensio ne r.
Pull ey a li gnm ent o kay a nd
Repl ace th e w o bbling pul roo m , lay a stiff m ec h a ni c's strai g h tmo untin gs a re so lid ? No matter how
ley- eas ier sa id th a n d o ne o n so me
accesso ri es . Bes id es th e prob lem s of
ed ge o r a thin stee l ro d across th e
ba dl )' th ey' re buri ed , in spect a ll t he
p ulleys . Look for chips a nd other
pull eys to he lp yo u d ec id e if t he p ul nea r-impossibl e access o n a fro ntph ys ica ll y d a maged secti ons th a t a lso
driv e's engin e, yo u may need to rent a
ley o n that n ew accesso ry is mi sspec ia l p ulley-p ull er tool if yo u do n 't
a li gned. Un less yo u wa nt to take
co uld co me in contact w ith the belt. If
own o ne.
back that accessory a n d check o ur
a ny of th e g rooved pu ll eys are packed
If t he pu ll eys a ren 't wobw ith road film , belt d ebris,
blin g but th e be lt isn 't tracketc.,
w ire-brus h th em clea n.
••
I'
in g we ll-see m s to twist
If t he sm oo th p ull eys (idl e r
s li g htl y o r m ove in a nd o ut
a nd wa ter pump) are obv ias it sp in s t he accesso ri eso usly worn o n th e belt-t rac kALTERNATOR
th ere may be pull ey mi sing a rea, you' ll have to
a li gnm ent. That is, one p ul in sta ll new o nes or a new
ley is just too far forward or
ten sio ner asse mbl y.
behin d a n other. Thi s happens o n new cars w hen m a n Doing It By Hand
u factu r ing tol era nces a re
A lot of o lde r eng in es-pa rexceeded , but it d oesn 't just
ti c ul ar ly o n J a pa nese ca rs"deve lop" unl ess yo u d id
sti ll have simpl e V-belts.
so me fro nt-oF-e ng in e wor k
Ma n y a lso have ribb ed be lts
a nd fa il ed to tig hten a ll th e
w it h manual ad justers. Th e
accesso ry mountin gs caretypica l adj uste r is a
full y. It a lso co uld h a ppen if
jac ksc rew ; just loosen th e
a n accesso ry rece ntl y was
lock bo lt a nd turn t he
cha nged , a nd th a t accesjac kscrew, co unterclockw ise
so ry's pull ey does n ' t lin e u p.
to loosen th e belt, cl ockw ise
(Did yo u just p ut in a new
to t ig hten.
a ltern ato r ? Power steer in g
Eve n if th e pulley is for a
p um p? Air-condi ti o nin g
simpl e V-be lt, it can acc u compressor? Water p um p?)
mul a te d e bri s in the g roove.
If th ere's enou g h access
So c lea n it o ut w ith a w ire
rep lace th e ten sion er. Neve r
" let go" of a tensioner. As ide
fro m th e possib le phys ica l
da nge r, t he sudd en release
ca n ca use intern a l parts of
th e tens ioner to snap (includ in g th e spring ). R e lease it
ve ry gra dually. If yo u do
need a new tensioner, d o n 't
thin k yo u have to ge t it fro m
a dea ler. Reputabl e afte rm a rket tensione rs a re ava ilab le fro l11 a uto m o t ive parts
stores .

;::
~~~~~G

REPLACING YOUR

BELTS

67

(Fig. 4) Don't check for correct
tension with the time-honored one-thumb
method. Use a gauge.

bru sh, ju st as yo u wo uld a multig roove. T he d ays of gettin g a n
acc ura te sense of belt tensio n by
pressing down o n a belt wit h your
thum b are lo ng gone . It takes a tens io n ga uge (Fig. 4) .
Although there are expensive professiona l ga uges, we' ve found th e Ga te
Kr ik- It ga uges do a good job a nd fi t
in to rea ll y tig ht pl aces. Look for the
lo nges t belt sp a n yo u ca n reach,
preferab ly at least a foot. Just lay the
Krik- It gauge at midspan, press down
slow ly on the center until yo u hear a
cricketlike click, then stop pressing.
The ga uge bar ri ses as it enco unters

belt tension, a nd stops when yo u stop
pressing. You ca n lift th e ga uge away
a nd read the po int of a lignment of the
edge of the bar w ith th e linear dial o n
the gauge ho using. Just turn down the
jackscrew to get the spec ifi ed tens ion ,
then tig hten th e lock bo lt.
You 're probab ly familiar wit h
" belt dress ing," a n aeroso l spray
for belt sq uea l. Use it o nl y to make
a q uick check of the belt as a
source of noise . Repea ted use r uin s
most belts. ~

HOW IT WORKS

Serpentine Belt
The serpentine belt is so named
because its routing resembles the
shape of a serpent. Carmakers developed the system so one belt would
drive several, if not all, underhood
accessories. A single belt, no matter
how long, saves space under the hood
since all the pulleys and accessories
are on the same plane and there's no
need to stack or stagger them. The
ribbed side of the belt fits into grooved
pulleys (each one a "mini" V) , and the
smooth back side of the belt often
wraps around the water pump pulley
and one or more idler pulleys. An idler
is used to route the belt so there's

plenty of " wrap" around each accessory pulley for good power transfer. To
maintain adequate tension for good
power transfer, and still eliminate the
need for periodic adjustment, an automatic tensioner is usually used.
There's a nearly infinite variety of
tensioner designs, but they all have a
powerful coil spring inside. The poly-V
belt design used on serpentine belts is
capable of transmitting more power
with less frictional loss than traditional
V-belts. A properly installed and automatically tensioned serpentine belt
system could remain troublefree for
four to five years or 100,000 miles.

L
68

MAINTENANCE

BASICS

•

ASY

Replacing Hood and Hatch Struts
hil e toppin g off yo ur tra nsm ission fluid o ne Satu rd ay
mo rnin g-hunch ed ove r th e
fro nt of th e engin e, dog a t yo ur sideyo u fee l th e to uc h of co ld stee l o n th e
back of yo ur neck. Yo u've rece ived a
weak "sta b " from t he car 's hood
la tch. Time, weig ht a nd wear have
consp ired to forc e a n un expected surrender of th e gas-cha rged hood suppo rt stru ts .
Un fort un ate ly, gas struts do wea r
o ut-a nd so metim es at th e mos t inopportun e moments. Weak o nes a re
more likely to fa il in co ld weat her,

W

..

REPLACING

when th e gas pressure ins ide drops a
little. Co nsequ ently, yo u' ll find that
th ese sa me weak struts work perfectly
we ll o n a ho t sum mer day. But th ey
sho uld still be rep laced fo r safety'S
sa ke. T he good news is th a t o ne
manu fac turer recen tl y introduced a
tempera ture-compensating gas strut
that sho uld elimin ate seasona l perfo rma nce va ri ation s.

Sizing up the job
Large, m o dern a uto pa rts sto res
ofte n have parts ca ta logs dang li ng
a t the e nd of eac h a is le. So yo u ma y

be ab le to look u p strut ap p licati o ns o n yo ur ow n. If n ot, ju st go to
the parts cou nte r a nd as k fo r he lp.
Be ca reful e it he r way. H oo d a nd
ha tc h st ruts come in man y diffe re nt
sizes a nd w ith seve ra l differe nt
m ounting ends.
Some emp loy a ba ll- joint mount at
eac h end . O th ers make d o w ith a ny
comb in a ti on of th e fo ll ow in g at
eith er end: a ball jo int, a no na rt icula tin g ha rd mou nt w ith a n integ ra l
hinge o r a Aa ttened pi ston-rod end
tab th at ma tes w ith a stationar y
mountin g peg. Some hood struts eve n

.....
:

HOOD

AND

HATCH

STRUTS

69

wo rr yin g t hat t he ot he r str ut is
go in g to let go .

Doing the double-joint strut

(Fig. 1) Slide the locking clip away from the mount ing leg to allow strut removal.
You might have to push or pull the clip to release it.

W it h a ll th e prep wo rk do ne, replacin g th e o ld st ru ts sho ul d tak e a ll of
a bo ut 10 minu tes. T ho se ba ll -jo int
en d s a re usua ll y he ld t oge th e r w ith
so me sort o f c li p : eit he r a flat C-cli p
th at m o unts t h ro ug h t he bac k o f t he
so c ket a nd g ra bs th e un d ersid e o f
t he ba ll , o r a w ire C-c li p t ha t sli d es
thro ug h th e bo tto m of the soc ket
a n d und er th e ba ll to p r eve nt
relea se.
Wedgi n g a b ig screwdr iver
betwee n th e shee tm eta l a nd t he ba ll
jo in t fo r leve rage is no t th e bes t way
to po p t he st ru t. A li tt le fin esse,
p lea se. Use e it he r nee dl e-no se pli er s
or t he sma ll es t screw d ri ve r yo u o w n
to ge ntl y p ull o r p r y c li p awa y fr o m
the socke t (Fig. 1 & 2) . Th en, simp ly pu ll t he soc ket off t he ba ll . Do
t he sa me thi ng a t th e o th er end. Sa ve
th e c li ps if t hey' re no t b roke n.
So met im es a n ext ra o ne co mes in
ha nd y.
Be car eful w hen wo rkin g o n
ha tc h stru ts m o unted nea r th e rea r-

have two sta ges . On t he Vo lvo 960,
be t he o n ly t hin g kee p in g th e li d
fo r examp le, u nl ock in g a p la st ic c lip
fr0 111 mee t in g yo ur head w it h a th ud .
o n eac h st r ut a llows th e hood to conO n a 2 -s tr ut d ea l, t he wood a ll ow s
t inu e openin g past ve rti cal for easier
yo u to w o rk on eit her sid e wit ho ut
engIn e servIce.
M ea sure th e f ull- open
(Fig. 2) This clip holds the socket onto the ball stud. Carefully remove the clip to release the
lengt h of yo u r ex ist in g st ruts sockets so you can pop off the struts.
befo re hea di ng o ut t o t he
p a rts store. T hen , c hec k t he
lengt h of th e new o nes
befo re go in g home . Or, tak e
on e of th e o ld str uts w ith
yo u for co m par iso n . It ma y
sa ve yo u a r etur n tri p . Be
awa re t ha t so me su ppo rt
st ru ts fo r o ld e r cars may no
longe r be ava il a ble in t he
tra diti ona l aft er ma r ket.
(T he 198 1 D a tsun 310GX is
o ne exam p le.) If th a t's the
case, you' ll have to visit a
d ea le r. O r m a ybe yo u' ll ge t
lu ck y a nd fin d th e st ru ts yo u
need in the .J. e. W hitn ey
cata lo g.
W ith the co rrect uni t (s)
in ha nd , open t he ho o d or
h atc h and p rop it up w ith a
sto ut p iece of w oo d. O n a
STRUT
I- str ut se tu p, th e woo d will

70

MAIN T ENANCE

BASICS

(Fig. 3) Insert the new strut's
integral ball stud into its
mounting hole and fasten it
with the nut.

-

w indo w defogger g rid. If
yo u slip w ith the sc rew dri ve r or pliers, yo u could
ruin the defogge r e lement.

Pop 'em in
To ease in stallation of the
new unit , m ount th e clip(s)
in a partially open position
on the new soc ket, and put
lube on the in sid e of the
soc ket with a littl e silicon e
grease . St ick the soc ket over
th e ball , then sna p th e clip
home. Repea t th is for th e
ot her end (and th e o ther
s id e, if app licabl e) a nd
yo u' re don e.
If yo u co me across a ba II
jo int tb at's not held togetber with a
c lip, see if th e ba ll end of the jo int is
sc rewed in to the sheetmeta l (Fig. 3) .
If so, it's very likely t hat a hex is
includ ed for removing th e o ld ball
w hil e it's still attac hed to th e strut a nd
screwing in the new strut's ba ll with
a n open-end wre nch. Look a t the new
str ut for guid ance.
For th e ha rd -mo unt t ype
of strut end , just undo th e
bolt, screw o r nut t hat ho ld s
the old strut in place, rem ove
it a nd attach the new p iece
(Fig. 4) . If yo u're dealing
with a peg-style mount, you
sho uld find a n E-cl ip of some
sort or a cotter pin preventing the strut end from slidin g
o ff the peg.
E-cl ips genera ll y need to
be pulled or pushed in one
di recti on or another in order
to release th em . Sometimes
just a gentl e nudge with th e
tip of a screwdri ver is

NUT

enough to pop them off. Oth e rw ise,
yo u may need to grab o ne of th e clip's
end tabs w ith need le- nose p li ers a nd
pull the c lip o ut of position. Th en,
remove tb e o ld strut, mount the new
o ne a nd slid e the E-clip back ho me
until you fee l it click or can see that it
is locked in.
Altho ug h th e str ut 's piston rod

has a ha rd ened corros io nproof a nd
weat herproof finish, yo u sho uld still
take care not to ni ck or sc ratch th e
po li shed surface . Thi s wo uld res ult
in th e marred metal ruinin g t he
str ut's ma in sea l. If th e sea l is damaged, the nitroge n gas wo uld lea k
out and yo ur bra nd-n ew strut wo uld
be tras h.

HATCH

(Fig. 4) Unscrew the hinge
from its mounting point on
either end to remove this type
of strut. You may even be able
to use a ratchet wrench and
socket.

REPLACING

HOOD AND

HATCH

STRUTS

71

Al so, do n't inad ve rtentl y m o unt the
new unit piston-side up, especia ll y if the
o ld o ne was piston-side down. Most
applica ti o ns-those th at contai n some
hydra ulic o il as well as nitroge n gas-

perform mo re smoothl y if o ri ented with
th e rod end down. Thi s a ll ows the mo re
effecti ve o il compressio n da mping to
occur later in the strut's st roke for ni fty
end cushi o ning upo n opening.

With the in sta ll a tio n co mpl ete,
pull o ut th e wood p ro p a nd enj oy th e
conven ience a nd safe ty of yo ur
hoods a nd ha tc hes stay in g o pen o n
t he ir own. f*

HOW IT WORKS

Support Struts
PISTON ROD MOUNT

PISTON ROD

SEALING ASSEMBLY

PISTON STOP
GROOVE

NITROGEN GAS

PRESSURE
CASING

In the old days, your heavy metal hood and trunklid
required beefy, space-robbing, spring-loaded hinges to
stay open. Then the carmakers tried flimsy prop-rods for
holding up the hood. But they invariably get in the way
during service and tend to wear out and break at the
pivot point on the radiator support.
So, as a result, gas-charged hood and hatch support
struts, or gas springs, have steadily infiltrated the market. They're compact, light, durable and relatively inexpensive-key for auto manufacturing in the '90s.
One of the slickest applications around is on the
Chrysler Cirrus/Dodge Stratus trunklid. No bulky suitcasecrushing hinges here, thanks to two stubby gas struts that
open the lid past vertical to allow for easier trunk access.

72

PISTON
ASSEMBLY

How do they work? Like tiny shock absorbers really.
But instead of being filled primarily with fluid for 2-way
damping, they 're charged with nitrogen gas for 1-way
expansion. One end is fastened to the inner fender or
cowl, the other to the hood or hatch. When you lift the
lid a little bit, it extends the strut's piston rod enough for
the gas to push on the piston and keep expanding the
strut. The lid has nowhere to go but up.
On closing, you're actually pushing against the gas
pressure to compress the strut back to its original size
and position. A typical gas support strut is designed to
last for at least 50,000 operations. They're maintenance-free throughout their life cycle but must be
replaced when worn out.

MAINTENANCE

BASICS

ODERATE
>-------

Resetting Your Emissions
Maintenance Reminder (EMR)
o ur o ld er m inivan has bee n a
tru sted me mber of the family.
It has helped you move yo ur
sister across town, kept yo ur kid 's
Litt le League van p oo l ro lling a nd
faithfu ll y transpo rted th e belo ved
dog to the vet. But it sure caused
havoc last wee kend . Leaving a t 5 am
wit h yo ur budd ies a nd a week's
worth of fishin g gea r, it sputtered,

Y

spewed black smok e from the
ex hau st a nd wo uldn 't eve n idl e.
Wa lleye w as ho ut!
It's bad eno ug h yo ur fishing pals
wo n't ta lk to yo u, but now th e
truck's go t to go in for ser vice. And
the on ly way to get to work is by
munic ipal bu s becau se your wife
needs th e Bimm er to ma ke a ll her
sa les ca ll s. Peachy.

Your Dash Is Talking To You
H o ld o n. Ha ve yo u bee n ignoring that
wa rnin g Iight on th e das h beca use
your "ca r gu y" brother-in-law sa id it's
no t importa nt? We ll, maybe it is. You
see, that warn ing light, wide ly used on
(Fig. 1) Press button on EMR relay to
reset reminder light for another 30,000
miles. This is an older Nissan engine.

SERVICE
REMINDER
RELAY

RESE T TING YOUR

EMR

73

pre-O BDII ve hicl es (befo re
va lve sea t opens a nd c loses
1996), is des igned to co me o n
smoothl y. O n la te-model co ma t abo ut 30,OOO-mil e interputer-contro ll ed EGR sys tems,
va ls, depend in g o n th e ve hicl e.
th ere may be no way to c heck
(Chec k yo ur ow ner's manu a l
the so leno id/val ve mec ha ni sm
for the spec ifi cs.) It's ca ll ed an
w ith out sp ec ia l tool s. If yo u
emi ss ions ma intena nce
haven't heard a n y engine p ing
rem ind er, or EMR, a nd it defi or kn ock late ly, id le qua lity is
nitely sho uldn 't be ignored .
okay, a nd if th e CH ECK ENG I E
When the EMR in d ica to r
li ght has n 't come o n, th e EG R
glows, it doesn't necessa ril y
system is probably fin e.
mea n tro uble. But each time
Other operation s you ca n
the light comes o n, the emischeck include the smog pump
sions system should be checked.
(o r p ul se-a ir system ) on eng ines
The idea is to work o n the
that use them . Exam ine th e
engine before the engine works
pump belt for cracks, wea r an d
yo u over. After giving yo ur
proper tensio n. Foll ow the
okay, the light has to be reset
(Fig. 2) Stick a pen or pencil in the back of the mileage
tubes fr o m the pump to the
counter in the cowl tray on Audis and Volkswagens to
so the system starts counting
d ive rter va lve and down to the
reset EMR system.
down for the next EMR cycle.
exha ust manifold a nd ca tal ytic
Th ere's a different reset
co nverter. l'v1ake sure th e rubprocedure for just about every
ber hoses a re intact and th e
MAINTENANCE
EMR system . Some indica meta l pipes and check va lves
REMINDER
tors, such as those o n most
a ren 't rusted o ut. You mig ht
CONTROLLER
C hrys ler light tru cks since
even be a ble to reac h under th e
198 9, ca n be reset o nl y by
ve hicl e a nd rap th e ca ta lytic
ta pping a sca n too l into t he
converter with a ma ll et or ham o n-board computer co ntrol s.
mer. A ra ttling no ise mea ns the
If yo u do n't ha ve a sca nn el;
cat has broken down interit's off to th e repair shop or
nall y- a nd its better days are
th e dea ler for ass ista nce. Some
behind it.
setups are reset by repl ac ing a
If yo u can see th e fu el-sysmodule. After a certa in num tem c ha rcoa l-vapor ca ni ster
ber of mil es, the modu le is
(sometim es it's buri ed in a
sim pl y le ft d isconnected.
front fender), in spect t he
There's no resetting prov isio n
integ rity o f its ru bber lin es a nd
a t a ll o n som e ve hicl es. Ju st
fittin gs . And whil e yo u' re at it,
disco nnect th e plug o r conneclook at th e a ir filter, a ir-box
tor to shut off the li ght.
(Fig. 3) You'll find Volvo's mileage counter under dash.
breather element and t he
Press reset switch to turn off light.
Still other EMR li ghts,
engin e's vac uum lines . Make
such as th e sensor wa rnin g o n
sure th e pos iti ve cra nkcase
mos t N issa ns (Fig. 1) , require no thing Checking Emissions System
ve ntil atio n va lve sti ll rattles w hen yo u
more t ha n a screwdri ve r a nd a bout 5
Th e key element in )'o ur emi ss io ns
sha ke it. C heck th e spa rk p lu gs a nd
system is the oxygen senso r th a t's
minutes of yo ur time to either pu sh a
wires and th e di stributor cap a nd
rotor (if app licable) for wear. Ultibutton o n a relay or pull apa rt a conmounted in t he exha ust ma nifo ld . It
nector-that is, after yo u've given the
senses if th e eng ine is runnin g too
ma tely, a ll powertra in components
rich o r too lean. When the O 2 senso r
ma ke up the em iss ions system , so
emiss io ns contro ls a o nce-over.
On ly und er th e fo ll owi ng three
check
w ha teve r yo u ca n get to .
gets la zy a nd stops reportin g acc ura te
cond iti o ns shou ld yo u consider resetinformati o n to th e electron ic engin e
Finding the Reset Location
control s, dri vea bility troubl e ca n
ting t he EM R li ght w ith o ut in specting
th e emi ss io ns system: 1. You've had
begin-a nd fis hing trips can be ruin ed . Alt ho ugh it var ies, reset-switc h locano drivea bi li ty troubl e a nd no CH ECK
tion s can genera ll y be broken down
So check o ut th e O 2 operatio n first.
ENG IN E li ght, 2. You've noticed no
Next o n th e li st is the exhau st gas
into three a reas: th e speedo meter
, appreciable cha nge in fu el eco nom y,
rec ircu latio n (EGR ) valve, if yo ur
ca bl e/fir ewa ll a rea, the kick
panel/under-dash a rea a nd the instruengine has o ne. Apply a vac uum to
:::d 3 . Your vehicle a lways passes the
the va lve's nipp le a nd make su re t he
L
te emi ss io ns tes t w ith fl ying colors.
ment panel a:a. Th e position s ofte~

I

74

MAINTENANCE

BASICS

In DOn d

MAINTENANCEREMINDER
CIRCUIT BOARD
INSTRUMENT
PANEL

(Fig. 4) On Chrysler minivans, you must remove the fuel gauge or tachometer to
get to the emissions-maintenance-reminder reset switch.

change from model year to model
year across the same vehicle make, so
a lways a pproach yo ur search with an
ope n mind . And check yo ur o wn er's
ma n ua I.
T he speed o cab le resets are usua ll y
the eas iest beca use th e ca bl e sticks o u t
li ke a sore thumb, and there's usua ll y
p lenty of room to work. Veh icles in
this category incl ude many models
from the early 1980s.
Aud is and Vo lkswagens are a
breeze. Yo u' ll find the mi leage counter
in th e cow l tray a t t he base of th e
w in dshi eld (the speedo cab le leads
right to it). There's a ho le on the back
of the counter. Stick a pen or pencil in
the hole and press in the rese t button
(Fig. 2) . You'll fee l the button lock in
place . T ha t's it. On Volvos, th e
mil eage counter is a lso in line w it h the
speedo ca ble. Once yo u've found th e
co unter, press its reset button w ith
your fin ger (Fig. 3) .
Still o thers are do ne from the insid e.
Drop the lower steering-column cover.
Feel for the sensor reset cable to the
left of the speedo cluster. Yank on the

RESETTING

YOUR

EMR

ca ble until yo u see the fla g reset itself
o n the left of the odometer.

Hunting for Switches
Vehicles tha t fa ll in to the seco nd ca tegory number too ma ny to ca llo ut
separa tely, but t hey a ll have some so rt
of EMR module, relay, connecto r o r
pair of conn ectors .
On some models, you 'll find a cancell ation switch on the right side of the
fuse panel. Press the switch to the O FF
positio n. O lder Fords hide EMR modules behind the passe nger kick panel o n
t heir tr ucks. Stick a small rod in the
hol e marked RESET. W hil e ho lding th e
button down w ith the rod, turn the key
to RUN and continue to depress the button for 5 second s. On o lder Jaguars,
the mileage counter is behind t he trim
in th e trunk. Press th e w hite button
w it h the key on to reset the light.

Pulling the Instrument Panel
Thi s third ca tegory can get complicated beca use yo u usuall y have to
dismantle p a rt of the da sh to remove
tbe instrum ent cluster o r a ga uge to

get in behind th e clu ster, as o n
C hr ys ler's mini va ns (Fig. 4) . Acco rd in g to a dia gnosti c hot lin e we a re
friendly w ith, th ese va ns a re th e ca use
of th e most EMR reset ca ll s. T he c ircuit-board-mo unted sw itch is tri cky
to fi nd if you don 't know wh at to
look fo r. It's mo unted behind th e fu el
ga uge o n th e sta nd ard c lu ste r or
behind th e tac ho meter on th e
op ti o na l clu ster. Someti mes yo u' ll
find a 9-vo lt battery in th ere, too . It
mu st be rep laced w ith an a lka lin e
battery. Some C hrys ler captive
impo rt li ght trucks ha ve a reset
switch o n the bac k of th e clu ster nea r
t he speedo juncti on or o n th e lower
ri g hth a nd co rn e r of t he cluster,
behind the face pane l.
On ea rl y- mod el GM ve hi c les, pull
the instrum ent cluster lens a nd use a
sma ll tool to p ush on the stem of the
orange plastic fl ag th a t pops up near
the odomete r. An al ignm ent mark
sho uld a ppear in th e left ce nter o f th e
odometer w ind ow w hen th e fl ag is
proper ly reset. Late- model GMs use
no spec ific EMR indica tor. Th e CHECK
ENG I ~E light illumin a tes if th e re's a
problem.
Earl y-model non-turbo Audis have a
cancel switch labeled oxs on the back
of the instrument cluster that must be
removed fro m the pod to ga in access.
La te- model turbos hide a mil eage
counter w ith a reset button under the
rea r seat. Some late-model BMWs use a
resettable mi leage counter. On 1989-93
Geo Trackers, locate the 3-w ire ca ncella ti o n switch in the ma in w iring ha rness behind the instrument clu ster or in
the steering-column lower-access pa nel.
You ' ll find th e reset o n th e bac k of
the speedo o n IsuZLI Troopers. Pu ll th e
tape from Ho le B and swa p the screw
from H o le A to Hol e B. Tape over
Hol e A. Mazda MPVs are simil ar.
Swap th e screw from H o le N O to
Hol e NC. Late- model M ercedes-Ben z
ca rs use no EMR in dicator. H oweve r,
1980-85s, o ther th a n th e 280, requ ire
bu lb remova l. On VW Rabbits a nd
Pickups, remove the instrum ent pan el
cover trim p late to get to the mileage
counter re lease a rms at the top left of
th e speedo hou sing. Good luck!

G

J
75

DIFFICULT

Passing An Emissions Inspection

the pintle of the EGR valve with a
screwdriver while the engine idles. If
the EGR valve passages aren't blocked,
the engine should stall immediately.

our car is running beautifully,
and all seems right with the
world. You have no trepidation
whatsoever when the time comes to
take it in for your state or loca l em issions test. After an interminable wait
in line at the inspection station, a
smiling, snappily dressed functionary
shoves a probe up your tailpipe and
asks yo u to gun it. Moments later, the
in spector sm il es wea ril y as he hands
you an envelope-not a new inspection sticker for your license plate, but
an envelope that says "FAIL" in
bright red letters. You have only a
month to do your hom ework and

Y

76

pass inspection. Heck, getting into
college wasn't this hard.
Wasn 't your car designed to meet
these emissions standards? Haven 't
you done your best to maintain it
with regular oil changes and tuneups?
What's gone wrong? And, most
important, how ca n you make it pass?
Take a minute to read the rejection
slip carefu lly. Typically, it will give
you the test results for your car a long
w ith the acceptab le limits. Note
which of the " terrib le trio"-hydrocarbons (HC), carbon monoxide
(CO) or oxides of nitrogen (NOx)-is
o ut of bounds.

Raw Gas
Hydrocarbon emissions are simply
unburned fuel being pumped raw into
the exha ust system. Misfiring is the
most likely culprit, and that can come
from an ignition problem, or an internal engine failure that reduces compression. Another possibility is a mixture that's too lean to catch fire
dependably because of either a fuel
system malfunction or a vacuum leak.
If a high HC number isn 't from a
miss, it's probably due to an overly
rich mix.
So, worn or fouled spark plugs are
the first things to suspect. If you can

MAINTENANCE BASICS

Older cars might benefit
from tweaking the idle
mixture screw no more
than a half turn in either
direction to get the idle
mixture setting correct.

C rankca se Ventil a ti o n
system a nd in to the
intake ma nifo ld.
Sme llin g th e d ipst ick
may tip yo u off to thi s,
a nd a n o il cha nge w ill
correct th e prob lemtem poraril y.

Killer Compound

feel a dea d mi ss a t idl e, use in sul a ted
pli ers to pull p lug wires one a t a time
to see if o ne in particular does not
have a ny effect o n smoo thn ess (don't
do thi s o n '96 a nd newer cars w ith
OBD II, as it w ill set a mi sfire code
a nd turn o n th e Ma lfu nctio n Indicator Lamp o n the dash) . Remove a nd
in spect t hat spark plug. If it's okay,
use a n o hmm eter to find o ut if t he
plu g w ire is op en-yo u sho uld meter
5000 to 20,000 o hms, t hen exa min e
the di stributor cap fo r heavy co r rosion in th e sockets, cracks, etc.
W ith the p lu g o ut, do
a compress io n testTIMING
a nythin g muc h less than
LIGHT
100 psi sho uld be suspect (a va lve m ay be
burned ). Also, look over
the intake manifold to
see if t here's a vac uum
tap in the runn er lea ding to the prob lem
cy linder. A leak here can
lea n o ut th e mi x to th e

po int of mi sfire at id le.
T here a re a couple o f other t hings
that ca n supp ly eno ug h extra gaso line
to put hydrocarbo ns above t he lim it.
O ne is the evapora tive-em issions cont ro l system th at trap s gaso li ne vapors
that wou ld otherwise escape into the
atmosphere. It t hen meters the vapors
in to the intake during off-idle modes
to be burned. If it fl ows at id le, t he
mix w ill be too rich.
Another potentia l cu lprit is engin e
o il tha t's diluted wi th gaso lin e. Fuel
vapors are drawn through the Positive

Many cars no longer
have adjustable ignition
timing, but you should
check it with a timing
light nonetheless.

PASSING AN

EMISSIONS

Ca rbo n mo noxide is
prod uced by incomp lete
co mbusti o n-th e
a ir/hie! c ha rge is ignited,
but isn't burn ing properl y o r entirely. In most
cases, thi s is due to fuelsystem tro ubl es th a t
make the engine r un
ri ch, but inta ke a ir restricti o ns co uld
affect it too. It's impor ta nt to no te
t hat so me combu stion is requ ired fo r
CO to be created. So, yo u won't see a
high CO rea din g if there's no spark.
W ith a carburetor, richness mig ht
be due to a n idl e mi x ture screw that's
open too mu ch, a heavy fl oat (the
foam type may absorb gaso line, a nd
the brass po ntoon type ca n develo p
holes a nd fill up wi th fuel), a c hoke
th at stays o n a fte r the eng ine has
warmed up , or a power va lve that
sticks in the open positi o n. Wi th fuel
in jection, perh aps th e
fue l p ress ure in the ra il
is too hi gh du e to a
fau lty fuel-press ure regul ator, or th ere may be a
cracked vac uum hose to
th e regul ator.
Of course, just a bout
a ny car built wit hin the
last two deca des w ill
have a n electroni c
engin e man age ment system th a t contro ls th e
a ir/fuel mi x ture (a mo ng
other thin gs), so co nsider the sensors that
_ _ _ _ _ _ feed informa ti o n ~

INSPECTION

77

VACUUM LINE

A cracked vacuum line can cause the charcoal canister
to malfunction, increasing emissions.
A misfiring cylinder may have bad rings or valves,
which can be spotted with a compression test.

to the computer. This, ho wever,
graduates into professional-level
troubleshooting.
On a precomputer carbureted car,
one way to get under the H C and CO
limits is to retard the ignition timing.
This w ill slow the idl e and provide a
longer, hotter burn. Then, bring the
idle speed back up to specs with the
throttle stop screw or idle stop solenoid , which will ad mit more air. Perfor ma nce will be off, but yo u' ll probab ly pass th e test .

Hard NOx
NOx is a tough one. It forms when
nitrogen (78 percent of the air we
breathe) combines with oxygen (21
percent of the atmosphere), which can
happen onl y at very high combusti on
tempera tures. The tro uble is, many of
the things that were initi all y done to
cut H C and CO involved dra matically
increas ing the heat inside a car's cylinders. That heat created plenty of NOx.
Fortunately, it was found that only the
peak temps (over 2500°F) produced
this smog-promoting gas, not the long,
hot burn th at oxidized the other two
pollutants. Introducing Exhaust Gas
Recirculation (EGR) knocked the top
off the tempera ture curve, thus putting
NOx within bounds. One of the main

78

reasons electronic
engine management
systems were developed in the late
1970s was to allow a 3-way catalyst,
which adds rhodium to the 2-way cat's
platinum and pall adium to further
diminish NOx.
The first things to suspect are an
inopera tive EGR valve (perhaps the
vac uum line is cracked, or the in te rn a l
diaphragm has ruptured) and carbonclogged EGR passages. Try app lyin g
vacu um to the va lve at idle. If th e
engine starts to r un ro ughl y or stalls,
the valve is okay and the passages are
at least partially open. Remove the
va lve and di g o ut all the depos its yo u
ca n.
There's a good cha nce th at th e cata lytic conve rter is no longer capab le
of reducing NOx, but determini ng
that requires high-tech diagnos is best
left to a professional. There's another
distinct possibility that yo u can dea l
with, however: heavy carbon deposits
in the combustion chamber and on
the backs of the intake va lves. These
can raise the compression ratio
eno ugh to ca use the hot fl as h that
forms NOx, and will also interfere
w ith the carefully engineered swirl
pattern of the incoming mixture that

makes it burn evenl y.
N umerous trea tments have been
devised to avo id the huge job of
removing the hea d and manually
clean ing the combusti on chambers,
piston tops and valves, but the only
one suita ble for the do-it-yourselfer is
chemi ca l treatment. The most basic
approach is to po ur a suita ble additi ve into the gas tank. A more thorough jo b can be achieved by adding
detergent- or solvent-based cleaners
directl y into the intake stream.
Too much hea t is another thing to
thin k about. Is the engine running
hot? Is the inta ke air overheated due
to a jammed Ea rl y Fuel Evaporation
va lve, or is a Thermostatic Air
Cleaner door in the snorkel stuck
closed?
Ignition timing that's too far
ad va nc ed can result in deto nation
tha t ca uses NOx to rise. A sw itch
to pre mium fue l may reduce it. A
final no te: Moisture-l a den a ir ca n
lower NOx o utput by as much as 30
perce nt, so yo u might consid er visiting the emissions station on a rain y
da y. fj

MAINTENANCE

BASICS

MODERATE

Changing Your Oil And Filter

T

he lin e at the quick-lube goes
around the building and nea rly
to th e street. But the a uto parts
store parking lot is empty-now's
your cha nce to show the wife that it
rea lly is cheaper a nd easier to cha nge
yo ur own oil. Especially after watc hing the grease-stained qu ick-lube
mechanic through the ba y doors for a
couple of oi l cha nges . Air wrenches
o n the oil -dra in plug? Even though
yo u rea lize that cars have cha nged
since yo u got out of the hab it o f

changing yo ur own, they haven't
cha nged tha t much.

All Jacked Up
J ack ing up the front of the car and
p utting it o n safety sta nds is still t he
first step, a nd placing the drain pan
under the oi l-dra in plug is the seco nd.
Okay, yo u're rea d y to loosen the p lug,
but it's rea ll y ti ght . That mechanic
w ith hi s a ir wre nch apparently was
the las t o ne to tighten it. Dra in plugs
typically have a soft metal was her or

a sea ling was her w ith a rubber insert.
Use a properly fittin g box wrenc h or a
6-po int socket wre nch to remove the
plug. Be carefu l not to rock the socket
to th e sid e as thi s co uld damage th e
f1 a ts on th e bolt.
If putting the ca r up on stands
doesn 't leave you eno ugh underbody
space to get adeq uate leverage, yo u
ca n use a 4-way lu g wrench prov ided
it has the proper end . Th is w ill allow
yo u to twist the bo lt w ithout add ing
a ny side thrust, and yo u' ll be ab le to

This permanent filter with a replaceable element is becoming more common on late-model cars. You need to
replace only the inner filter element,
not the entire cartridge.

CHANGING YOUR

OIL AND

FILTER

79

use both hand s a nd a ll of
yo ur upper-body strengt h.
Remain ca lm , have pati ence
a nd yo u' ll get it loose.
But of course, li fe isn 't
easy. The threa ds in the pan
a nd o n th e plug are damaged,
perhaps from partial crossthread ing. What to do now?
Forget the drain plug a nd get
a repa ir kit. A t ypical kit has
a rep lacement fitting tha t cuts
deeper threads, a nd when
ti ghtened, it sea ls against a
washer and remains in p lace.
So me kits cut fresh, deeper
threa ds for a new plug . A
hexhea d brass cap w ith a n 0rin g sea l threads onto th e
end. W hen it's time to c ha nge
t he o il, yo u unthread the cap.
O th ers (for odd-size, severe ly
damaged ho les) are fa t, coneshaped synth eti c rubber plugs
large r th a n the drain-plu g
ho le. You fo rce a spec ia l rod
into a n ope ning in th e cone,
w hi c h tempora ril y stretches it
A simple band wrench may be all that's necessary to remove a canister filter. Make sure
a nd reduces its diam eter,
you have enough room to swing the wrench.
a ll ow ing it to fit in t he ho le.
Withdraw the rod, and the
course). If th e drain plug is okay a nd
pan is dra in ed, unthrea d the hose fitcone relaxes and sea ls t he ho le-the
ting (the va lve sp rin gs shut), rein sta ll
yo u want to reuse it, rep lace th e
cone won't come out until yo u force
th e fin ge rti ght cap a nd you' re good to
was her a nd t hen tig hten the p lug to
in th a t rod to stretch it.
If th e dra in p lug looks marg in a l,
go (a fter c ha nging the fi lte r a nd
spec ificati o ns-20 ft.- lb. to perh a ps
co nsid er insta lli ng a Fra m o il-dra in
putting fres h o il in th e engine, of
35 ft.-lb.-depe nding o n th e size of
va lve kit. These are avai la ble
the plug.
Empty the drained o il
for the most com mo n types of
drain-p lug ho les. Thread a
into a suitab le container.
spring- loaded va lve asse mbl y
(In my area, th e county
w ith a copper was he r in to the
gives away flat jugs w ith a
ho le a nd tighten. Th e va Ive is
giant built-in funnel.)
th e primary o il sea l, a nd a
When the jug is full , take
knur led cap threa ds on finth e o il to the store w here
ge rti ght aga in st an O-ringyo u bought the new o il to
thi s keeps out dirt.
be emptied into a n o il-recyWhen it's tim e to dra in o il,
c ling tank. Ma ny sta tes
unthrea d the cap and threa d
req u ire service sta ti o ns to
o n a fittin g w ith a drain hose,
take small q ua ntiti es of o ld
w hi ch you can a im rig ht into
o il. Dump ing o il in th at
th e pa n (no splatter and no
low spot behind the shed or
ho t oi l running down yo ur
in to the sink is not accep ta rm ). T he hose fittin g has an
A spider-style wrench
interna l tip th a t push es open
may be more suitable for
th e spri ng- loa ded va lve, and
filters that are not easily
the o il dra in s out. When th e
accessible.

80

MAINTENANCE

J

BASICS

Sometimes th e end of a fil ter has a hexn ut in the center,
so you could use a conventional wrench. If yo u can't
find the right size and shape
cap wrench, try one of the
following:
• Ny lon band wrenc h.
This universal too l wraps a
band aro und the filter ti ghtl y.
• Coi l-spri ng wre nch. It
'-...... INSERT
PLASTIC ROD
fits over the end of the conIN OPENING
ventiona l spin-on filter, and
This filter has a rubberized area to
the band coil extends to near
provide for tightening by hand.
the filter's base. Turn the end
""-- PLASTIC ROD
w ith a wrench and the co il s
able-and probab ly is ill ega l where
tighten around th e entire filThis simple rubber plug can rescue a strippedyo u li ve .
ter. This prevents damage
out oil-drain-plug hole. Insert the rod to install
and separa ti on from the
Off With The Filter
base .
How a bout dri ving a big screwdriver
When removing an oil fi lter, what you
• Spring-band wrench. This
thro ugh the spin-on cartridge and
need more than anything is the appro- wre nch fits over the end of the filter
using that to loosen a stuck filter?
priate wrench. There are many sizes,
and extends just past the fI utes, so it
You're more likely to destroy the cargri ps th e full circle of the filter bod y.
and perhaps the most common
tridge and still not loosen the filter.
a nswer is the cap wrench, w hich fits
• A "spider" has three fluted legs
Have the dra in pan in place, sitting
that cla mp against the sp in -o n caron the end of the filter. Only probl em:
on a spread of newspape rs or an oi ltridge and " di g in, " preventing slipThe wrench fits aga inst a fluted patabsorbent pad- just in case. Once the
page. It has an end plate for a ratchet,
tern and there are countless fluted
filter is loosened, oil ma y start flowin g
and because the sp ider legs extend 2 ~
patterns. So not only do yo u need the
to th e gro und.
right size, but the right internal shape
in., they grip well past the o uter end
Unthread the filter and carefully
to fit the flutes . The one tha t fits the
of the filter. This design provides well empty it into th e drain pan.
distributed gripping power.
filter on yo ur car now, we should
It is possible to loosen a badly
warn you, may not fit th e replacement
Refilling
stuck filter with a good filter wre nch.
filter yo u buy.
App ly a film of cl ea n engine oil to th e
gasket of the new filter, then threa d
the filter on by hand. Some filters
WHAT'S THAT STARBURST?
have a rubberized surface to make it
easy
to turn. Every reputable oil filter
You should see two labels on a container of oil. One is a
is
designed
to seal for tens of thou"starburst" with the words American Petroleum Institute
sands
of
miles
with no more than a
Certified printed on it. This means that the oil has
good
hand-tightening.
You don 't need
passed tests for the recommended service in which
a wre nch unless yo u have one of those
it's to be used-that includes a test by ISLAC (Interdeeply recessed filters with no space
national Lubricant Standardization and Approval
around it for yo ur hands. (If that's the
Committee). Passing the ISLAC oil test enables carcase, the only choice is a cap wrench.)
makers to add to their fuel economy numbers. Oils
Turn the filter until yo u feel the filter
such as OW (a synthetic grade) and 5W (thin) pass this
base just make contact with its
test, and so do some lOW-30 oils. Heavier oils, including
mounting plate. Then use the wrench
those formulated for older cars, do not.
to tighten a ha lf-turn more.
On the second label you'll see the words "Energy Conserving." Real
If yo u haven 't bought engin e o il
world: Oils labeled this way won't make a noticeable difference in your
in a whi le, you may be confused by
car's gas mileage. This label also lists the service category. On late models
th e choices. For a little fri endl y
you want an oil deSignated For Service SL. You may also see some Sl/SJad vice, see "What 's That Starburst? "
rated oil on shelves. Read your owner's manual.
left. tJ

CHANGING YOUR

OIL AND

FILTER

81

DIFFICULT

Search Engines
o ur tempera ture ga uge inches
up towa rd the danger p o int.
Simulta neo usly, traffic slows
eve r closer to mp h-w it ho ut eve r
qui te reachin g it-as the ru sh h o ur
dee pens. T here's no a ir mov ing
th ro ugh yo ur radia tor, a nd an y that
does is too da mned h ot. Yo u start to
smell that sy rupy-sweet panca kebrea kfas t-in-a-Tu rkish-bath odo r o f
nea r-bo ilin g a ntifreeze . You turn off
the alc to redu ce the load, but th e needl e does n't d rop. Time to upgra de the
coo ling system.
After spending a full Sa turday and
$4 50, you 've installed a high-perform ance rad iato r and th e pro blem d isa ppea rs. Th en, yo ur fr iend w ith the
sa me make o f ca r has the same p ro blem. So yo u tell him the good- if
ex pensive-n ews . "1 a lso got the
prob lem fi xed," h e tells yo u, " but it
cost me onl y $75 at the car dea lersomething a bo ut reprogra mming the
co mputer. Th e car was o ut of th e
pl ace in a ha lf- ho ur."

Y

82

°

Reprogra mm ing toggled the coo lin g fa n on and up to hi gh speed much
ea rl ier, usin g a rev ised fan co ntrol
a lgorithm . If onl y yo u had known .

Look It Up
Now yo u can know. You can do
more- and better-wo rk on your car
with the spec ia l manu a ls, bull etin s
a nd some of the specia l too ls th e
dea ler shops have. In fact, yo u even
ca n rep rogra m yo ur ca r's co mpu te r
us ing yo ur PC and a generic device
th at works on a ll makes. Yo u thought
all that was secret stuff or incred ibly
expe nsive ? Not an ymore-it's ava ila ble to everyo ne fro m fac tory tec hserv ice Web sites. As ide fro m a shop
uni fo rm , anyt hing the dea ler tec hs
get, yo u can too, in clu d ing o ncesecret me mos . O nl y a few low-vo lu me
cars, such as Ferrari, R o lls-Royce,
Asto n Martin, etc., are exemp t.
Virtuall y every Web site meets or
bea ts a cost of $20 per day for a ll
in fo rmati on (except BMW at $25 per

day, Porsc he and VW/A udi w ith a
per-d ocum ent price). Hyund ai and
Kia sites a re free, and others offe r
some freeb ies even if yo u don 't bu y
anything.
We b site informati o n is " professional," intended for service technicians w ith ve hicl e-specific training
program s under their belt- so yo u
may need to go slow ly to und erstand
it. Howeve r, most sites have tutor ia ls, even o nlin e a uto tech co urses
yo u can ta ke, as we ll as techni ca l
ma nua ls to rea d . T hey're designed for
bas ic trainin g, so they won't lose a
Sa turday mec hanic.
Most of the We b sites h ave p rett y
stra ightforwa rd nav igation, but it's
still not like o pening a boo k. Always
read t he system req ui re ments and freReprogramming your car's engine management computer is only slightly more
complicated than downloading music
onto your MP3 player. The pass-through
device connects the car's OBO II diagnostic connector to your computer.

MAINTENANCE

BASICS

q uentl y as ked questi o ns (FAQ ) fi rs t.
High-speed Intern et serv ice ma y be
just " reco mm end ed ," but w ith o ut it
yo u' re in for rea l frust rati o n, both for
downloa ding speci a l so ftwa re a nd
using certa in features . Some downloa ds a re over 15MB, and yo ur actu al
tra nsfe r speed may be far less th a n th e
connecti o n ra te- mea ning litera ll y
ho urs of downl oa ding. Th ro ughpu t
ra tes mi ght be better in th e wee ho urs
w hen there's less traffic o n the Internet . After yo ur days-l o ng subscription
to th e Web site expires, yo u ' ll still
wa nt access to the da ta yo u've paid
fo r. So print o ut the service data as
yo u d ownl oa d it, o r a t least keep it o n
yo ur hard dri ve a nd backed up to
so me o th er pl ace.

Favorite:;

SEARCH

ENGINES

Help

l

Addfes!;

/

Se~ch

Favorites

Modi· e

.iJ http://\oIIWW ../IldatMliy .com/alld~It/AFJ .....'V332282i'''(37~6s--.RQ.vOFi2''''N/O'779939S6/9 1 3 11'1'15/91 3 111'1 619 1 3 11 449/34; v

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r\'lce bulletlf'l$ (TSBs) afe

• 200S
,

NI!:HAN..!!,.","<"",,,,-,,,,,,pc,,,hn,,-,'C>,,,,p,,~<' - -_ _ _

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• 2405

$1600 now.
Web site service informa tion and reprogramm ing are
leve ling the playing fi eld for
you in your home garage, and
for the independent garage
yo u may patronize.
tI

()'~e'

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to,

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Tech Web Sites
Most tech Web sites (take note of the exceptions below)
take the form: www.nameofvehicletechinfo.com . Example: www.landrovertechinfo.com.
• Alldata Do-It-Yourself: www.alldatadiy.com (excludes
Honda/Acura and BMW coverage).
• Chrysler Group: www.techauthority.com $20 for a day
of TSBs dating to 1992, and all service/diagnostic information to 1996 (a few '95s). Good selection of Chrysler
training materials for subscribers.
• Ford (and Lincoln Mercury):
www.motorcraftservice.com Free selection of OBD II
training books, owner's manuals and towing/camping
books. It's $10 per day for TSBs from 1988 on and $20
per day for all repair information on a single
model/year/car, which includes service/diagnostic information and an e-mail link to OASIS, the Ford factory-tech
help line.
• General Motors: www.acdelcotechconnect.com Free
access to "Tech Link," a monthly professional tech service magazine that covers a wide range of GM service
issues, with archives back to 2000. Pay $20 per day for
bulletins (from 1980) and all service/diagnostic information (1998 on, with powertrain manuals back to '96).
• Honda and Acura: www.serviceexpress.honda.com Buy
access separately for $20 for three days. Selecting a
subject (such as Fuel & Emissions) gets you information
from the service/diagnostic manual, applicable service
bulletins and anything on the subject from "Honda Service News," a dealer technician publication.

84

• Hyundai and Kia: www.hmaservice.com Entirely free,
includes good training you can download , as well as service/diagnostic information.
• Mercedes-Benz: www.startekinfo.com A $20-per-day
site loaded with technical information going back to the
early 1990s.
• Nissan and Infiniti: www.nissan-techinfo.com and
www.infinititechinfo.com lt.s $20 per day for access to
both sites (bulletins back to 1987, service/diagnostic
manuals since 1994). Manuals come up by subject and
read like a book.
• Porsche: http://techinfo.porsche.com (no www)
• Subaru: www.subaru.com (then click on home, and then
technical information).
• Toyota and Lexus: http://techinfo.lexus.com and
http://techinfo.toyota.com (no www) Get both easy-touse, info-packed Web sites for $10 per day. Included are
diagnostic/repair manuals, wiring diagrams and bulletins
since 1990.
• Volkswagen and Audi: https://erwin.audi.de (no www)
and www.erwin.vw.com Separate Web sites are run by
the same office in Germany. You're charged by the document, so click repeatedly on Search, which gets you to
the price and Contents.
• Volvo: www.volvotechinfo.com Sells service/diagnostic
documents, wiring diagrams and two types of service bulletins for three-day periods. Manuals are $10, diagrams
$5 and the bulletins $13. The sales are only for specific
models, except wiring diagrams.

MAINTENANCE

BASICS

•

ASY

Charging Your Battery

S

pring has come an d go ne.
Wit h th e ya rd fina lly
w hi ppe d in to shap e, yo u 've
m a naged to sc hedu le a lo ng weekend up in th e mounta in s- just yo u
a nd yo ur fa mi ly and a few d ays of a
lot of nothing . The motorhome
starts w ith the aid of jumper ca bl es,
and a fe w hours of fr eeway dr iving
sh o u ld fu ll y c ha rge th e ba tte ry. The
sa d p a rt is, when yo u fina ll y reach
th e camps ite, the kid s ca n ' t watch
TV, th e microwave won 't wo rk a nd ,
horro rs, th e blender is incapa ble of
making yo ur favorite froze n concoction. The battery ha sn 't charged much

at a ll. Yo u co uld run yo ur generator
o r the motor-h o me engine for power,
but yo u ha te to di sturb the untram meled w ildern ess by doing tha t. And
bes ides, the ca mpgro und ha s ru les
aga inst genera tors after sunset.

Too Close To Home?
The prob lem yo u have is common to
ma ny RVs, a nd there are many possible reaso ns for yo ur predicament. The
RV's deep-cycl e ho use battery was left
unc harged over the winter, ftoze a nd
is now use less except as an anchor for
yo ur boat. Or, you simply forgot to
turn on th e battery switch. Or, the

alte rn ato r o n the RV was maxed o ut
by running the alc fa n, GameBoy and
stereo a nd trying to rec harge th e ba ttery a ll a t the same time.

How Batteries Charge
A conventiona l lea d-acid car battery
is filled w ith interl eaved p lates of
spongy lea d and lea d d ioxide soa king
in sul furic acid and water electtol yte.
The sulfu ric ac id is diluted to a specific grav ity of about 1.26 to 1.30,
depe nd ing o n th e type o f ba ttery.
C harging the battery combin es so me
of the sulfuric acid a nd lead, reducing
the concentra tion of sulfuric acid
Motorhomes, tractors, boat s,
motorcycles and other occasionaluse vehicles should use a batterymaintainer style of charger to
prevent battery damage.
The permanent extra
wiring harness makes it
easy to hook up the
charger when
necessary.

CH AR GI N G Y OUR

BAT TE R Y

85

With hard-to-access batteries, look for
a remote jumper cable post.

FUSE BOX COVER

down to a bo ut 1.12 and coa ting the
plates with a la yer of spongy lead sul fate . Reversing this p rocess gives yo u
back most of that electricity. This
means that checking th e specific gravity of the electrolyte is a very good
wa y of finding o ut the actu al state of
charge of a battery.
It's a lso fu ssy and po tenti all y dangerous if the battery electro lyte end s
up someplace it's not supposed to be,
like in yo ur eye or on th e lea ther
upholstery of your wife's ve hicle.
Also, some maintenance-free batteries
have no fill er caps a nd there's no way
to check o r a dd electro lyte.
So, we' re left to estim ate the battery's state of charge by rea ding its
in the electro lyte develops a gra dient,
voltage. A fully charged 12-volt batbecoming more concentrated next to
tery sho uld have an open-circuit vo ltone plate and less concentrated at the
age of 12.6 volts. A discharged batoth er. Onl y time wi ll even this out,
and tha t's why yo u can't qui ck-charge
tery will have a vo ltage of abo ut 11.2
volts-but these numbers need to be
a battery to any more than a bout 50
checked w ith no loa d a nd with sevpercent of its capacity.
era l hours o f res t after charging. And
To charge a battery, a charger or
this is at a norma l battery tempera yo ur car's altern ator needs to ra ise the
ture of 80°F-colder batteries
have a slightly lower vo ltage .
An RV parked outdoors is a good candidate for a
A battery left disch arged fo r
battery maintainer, such as this type.
eve n a few ho urs w ill conve rt
SOLAR BATTERY
some o f its so ft lead sul fa te
MAINTAINER
depos its-the kind th at rea dil y
change back into lea d oxide
and sulfuric acid-into hard
permanent deposits . These
deposits interfere with normal
battery operation, and ca n
damage the plates.
Be ca reful when storin g batteri es in lower temps. A di scharged battery co ntain s
mostly water and ca n freeze
solid , fracturing th e lea d
plates. Always store a battery
full y charged and in an area
that stays a bove freezing.

Uphill, Downhill
As a battery is charged o r discharged , electrolyte needs to
diffuse fr om one plate to
another. At high or low discharge or charge rates, th e acid

86

voltage across the battery posts. No rmal charging voltage needs to remain
below a bout 14.4 vo lts, which is the
level at w hich gass ing of hydrogen and
oxygen starts. Yo ur ca r alternato r was
never intended to charge a tota ll y di scharged battery. H ere's what happened on th at fa teful trip to th e mountai ns. The ba ttery was to tally d ischarged after being left unattended for months. A totally
solar
discharged battery needs very
high vo ltage (ove r 16 vo lts) or
a long cha rging time at 14 volts
to even begin to acce pt a
charge . O nce th at battery
started to accept a charge (but
in this case it did not ), it wo uld
have made the a lternator work
very hard to pump current into
th e battery, shortening the
altern ato r's life.
This type of situation ca lls
for an external battery charger.
The tra ditiona l charger is a simple transformer and diode affair
that charges a battery to a constant voltage just below the
gassing vo ltage of 14.4 volts. It
will sta rt OLlt chargi ng at a good
clip, and then tape r off, taking
as much as a full day to full y
charge a large, dead battery. It's
not a candidate for keeping a
battery charged, because the
voltage it genera tes w ill still

MAINTENANCE

BASICS

HOW IT WORKS

There Are Batteries,
And Then There Are Batteries.
We commonly think of car batteries as lead-acid
flooded wet-cell batteries that haven 't changed substantially since the earliest electric cars used them
(the early batteries' cases were made of glass, not
plastic). The lead in these is alloyed with antimony to
make it hard enough to withstand the vibration it
receives in a moving vehicle. In the last few generations, maintenance-free batteries have become the
standard. These use an alloy of lead and calcium. In
contrast, the antimony used in older batteries promotes the electrolysis of water, lowering the electrolyte
level and requiring replenishment. Maintenance-free
batteries generally have a higher level of electrolyte
covering the plates, and they commonly lack filler caps.

Totally discharging one of these types of batteries even
once can permanently compromise its ability to take a
full charge. Deep-cycle batteries use a purer lead in
thicker plates, and are capable of many cycles of neartotal discharge. They need periodic replenishment of
the water in their electrolyte.
The newest lead-acid battery technology uses a gel
electrolyte that won't run out if the battery or vehicle is
upended. Another type becoming popular is the
absorbed glass mat (AGM) cell. The electrolyte in this
battery is held in a spongy mat and can't move around.
AGM and gel-cell batteries internally recombine the
hydrogen and oxygen from electrolysis so you never
have to add water to them.

A smart charger will rapidly recharge a
dead battery without boiling off electrolyte.

ma ke the electro lyte disappea r as
gases- an especi a lly bad idea for a
maintenance-free battery that ca n't be
replenished. Even a small trickle
charger will damage a battery over a
few months if left on.
The more modern battery chargers
are smart. They w ill ra ise th e curre nt
fl ow hi gh eno ugh to bulk charge th e
battery rap idl y, then taper off until
th e battery is full y charged . Thi s
reduction is necessary to keep below
the 14.4-volt ga ssing point . Th e
chargers then throttle back to a somewhat lower voltage that w on 't bo il
the electrolyte, and peri odica ll y check
Voltage is a good indicator of a battery's state of discharge, but not during the charging phase.

BATTERY VOLTAGE AND STATE OF CHARGE

15
14
~

13

==

"
In
:III
In

CI)
~

....I

12

0

>

AMPEREHOURS

11

c:
:III
CI)

10
9

CHARGING

DISCHARGING

TIME

CHARGING

:z:

o

YOUR

BATTERY

the vo ltage, occas iona ll y ra ising the
voltage for a fe w hours to maintain a
full charge .
The latest cro p of smart chargers
even have a battery-reconditi oning
fun cti on tha t is supposed to break up
ha rd sulfate depos its by bl asting them
w ith p ul ses of high-frequ ency vo ltage
spikes, returning a badl y sulfated battery to near-new condition .l spikes,
returning a badl y sul fa ted battery to
near-new co ndition.
~

87

88

CHAPTER TWO

•

In
Today's Tuneup / 90
Smoothing Out a Lumpy Idle / 93
Replacing Your Water Pump / 96
Curing a Clicking Starter / 99
Repairing Cooling System Leaks / 102
Curing Slow Cranking / 105
Finding Oil Leaks / 109
Flushing Your Cooling System / 112
Checking Your Ignition Timing / 116
Replacing Engine Mounts / 119
Cleaning Throttle Bodies / 122
Electric Cooling Fan Problems / 125
Finding Engine Knock / 128
Plugging Leaks / 132
Turning Up Your Heater / 135

89

EASY

Today's Tuneup
RETAINING CLIP

T

here's the thruway exit, but
you're stuck in the left lane.
H ey- a break in the traffic. You
fli p up the tu rn signal, floor the gas
pedal and try to edge into the right
lane. Whoops! Your V8 is embarrassed by a 4-cylinder econobox with
the same obj ective. It was behind yo u,
but it apparently has better accelerati on. You hit the brakes, crank the
wheel to get back into the left lane,
cru ise to the next exit miles and miles
ahea d , and make the time-wasting
U-turn. The Wife suggests a tuneup .
But we don't tune up today's engines,
right ? They're computerized and
there's nothing to adjust.
Wrong. It's true we stopped replac-

90

ing ignition points over 20 years ago .
If it's rea lly a late-model vehicle, it
may not even have a replacea ble fuel
fi lter under the hood. The battery is a
fill -free des ign. And there's no ignition
timing to adjust. H owever, while it has
changed signific antly- even in the last
seven or eight years-the concept of a
tuneup itself is anything but gone.
Emissions reg ulations may have
tightened, but am bient air is still
di rty. So the air filter still plu gs up,
and the engine gasps for brea th until
a clean new fi lter is install ed (Fig. 1) .
Gasoli ne is unleaded, so spark plugs
don't lea d-fo ul anymore, and the new
prec ious-metal designs last much
longer. But they aren't guaranteed to

(Fig. 1) Replacing the air filter will
require popping off a couple of clips.
Slide the new filter into place, be sure
it seals properly, and replace the cover.

last a life time, and engin e performance often ca n improve when p lu gs
are replaced well before the owner's
manual dictates.

Underhood Checks
A good wa y to start today's tune up is
to look for tro uble codes, using a scan
too l. Th e only codes that turn on a
Check Engine light are those th at
directl y impact emissions, provided
the computer can detect them, to keep
people from getting nervous. Most

ENGINE

codes show up o nl y w ith a scan too l.
O n th e o th er ha nd , " no code" driveab ility prob lems a re a lso extre mely
common.
If yo u find a trouble code, yo u
sho uld trace the circ uit to pinpoint
the problem. Sure, it cou ld be just a
bad senso r, but it may be a bad wirin g
conn ecti o n, chafed wire o r damaged
hose. Yo u'll need t he facto ry se rvice
in formation to be ab le to do thi s.
No t roub le code? In spect under th e
hood. look for dama ged vac uum
hoses that sho uld be repl aced, loose
connections at a ny of the sensors and
soleno ids, tears in th e a ir clea ner
du ctwork, a disconn ected duct o r
poor spark plug wiring co nn ec ti o ns.
Test th e be hav ior of th e engin e
co ntro ls a nd th eir sensors. Th ere sti ll
a re tim ing m arks on man y la te models an d if yo ur ve hicle is one of them,
yo u ca n check ba sic timing (a t idle)
w ith a timing light. No mar ks? You
still ca n chec k igniti on timi ng o n t he
sca n too l by rea din g th e ig niti o n
advance data item. look fo r a stea d y
in crease in ignition timing as the
thro ttle is gra duall y opened from idl e
to a mid th rottle position .
Even if th e timing is a ll right, check
the th ro ttl e position sensor a nd intake
airfl ow (mass a irflow ) sensor readings, w hi ch a lso sho uld show grad ua l
increases as the accelerato r peda I is
dep ressed. At the same tim e, tap o n
the mass airfl ow sensor w it h a screwdri ver handle and if th e engine hi ccups or the sca n tool read ing spikes,
the senso~' is defecti ve.
A coo lant temperature sensor sho uld show a co ntinu ous
in crease in th e reading until t he
eng in e is full y war m (195 ' F to
230' F). A MAP (manifo ld
abso lute p ress ure) engine vacUU111 sensor should show
cha nges w hen a pinched-cl osed
hose suppl ying vacuum to it is
released (Fig. 2) . Th e engine
sho uld read a bout 750 to 850
rpm at idle w it h the engin e
(Fig. 3) Wiggle the wiring connectors while the engine is running
to check for misfires.

TODAY ' S TUNEUP

• , I

1I I I I 1

MAP
SENSOR

(Fig. 2) Check the MAP sensor with a scan tool by pinching its hose.

warmed, a nd increase g rad ua ll y as t he
gas peda l is dep ressed.
Stil l no reason for a dr iveab il ity
glitch ? Yo u need to access the powertra in computer. It may be located
und er th e hood o r under the dash. T he
most comm o n und er-dash loca ti on is
behin d the passenger-s ide ki ckpad.
Remove t he kickp ad a nd , w hil e a
he lper is slow ly acce lerating the
engine, flex the computer w irin g connectors a nd tap o n th e co mpu ter ho usin g (Fig. 3) . If th e engi ne hi cc ups,
there's a bad connectio n or poss ibly
cracked so lder jo ints o n th e circuit
boa rd . Yo u may need a rep laceme nt.

Replacing Spark Plugs
Time was, spa rk plugs were always
vis ible, even if it took a struggle to

reach th em . Now t hey're often
recessed into th e hea d, and in m an y
cases th ere a re no p lu g wires . A mini
igniti o n modu le, perhaps wi th t he co il
bui lt in to it (o r into th e plu g boot), is
used in stea d. Yo u may have to
remove a cove r t ha t ho ld s t he igniti o n
modu les a nd plug boots fo r access .
W hatever th e des ign, very carefu ll y
make a n y necessa ry electrical disconnectio n at the plug prior to plug
remova l. If th ere a re plug wires, grasp
a nd lift by the plug boots. Never pull
o n a plug w ire o r it may separa te
internally. Look inside t he boot a nd if
it appears soaked in o il or cracked by
hea t, rep lace it. If the igniti o n co il is
bui lt in , expect it to be pricey.
In spect th e p lugs. If th ey a ll have a
coa ting of bl ac k carbon, th a t indi ca tes a rich fuel mi x ture and
lik ely a bad oxygen sensor. A
sca n too l sho uld be ab le to
pinpo int a ma lfuncti on ing
oxyge n se nso r eve n if it did n't log a tro ubl e code. If
th ere's just a single carbonblacke ned plug, yo u probab ly
have a leak in g fu e l injecto r.
W hen yo u' re ready to
in sta ll the new plug, apply
a thin film of a ntiseize compound so th e new plug
doesn 't hea t-sea l in p lace .
Use a torg ue wrenc h to
tighte n the plug.

J
91

bru sh bOth contact faces even
if they look clean. Make sure
the bolt threa ds in with o ut a
feeling of looseness, a nd if
there is a ny, don 't try to muscle
the bo lt supertight with a
wrench. You're more likely to
m a ke things worse.

(Fig. 4.) You may not be able to
clean the pintle on a recessed
EGR valve like this one.

Exhaust Gas
Recirculation
Exha ust gas recircul ati o n
(EG R ) va lves may stick o pen,
fa iI to cl ose co m pl etely o r just
no t o pera te smoothl y. If so,
th e engine w ill hes ita te a nd
may sta ll , fuel econo m y may
d ro p, a nd emi ssio ns may be
affected-even if yo u p ass th e
sta te in specti o n test. The
EGR valve meters so me
exha ust gas bac k into th e cy lind ers to
lower pea k tempera tures of t he airfuel charge during co mbu sti o n . Thi s
not o nl y redu ces a key po lluta nt
(ox id es of nitroge n ) but often
improves fu el eco no my. Th e EG R
va lve, t ypica ll y a di ap hrag m-actu a ted
dev ice w ith a pin -type va lve, is pull ed
o pen by engin e vac uum , but th a t vacuum mu st be precise ly reg ul ated. Too
mu ch vac uum res ults in too much
ex ha ust gas fl ow, whi ch ca n ca use the
engine to lose power, even sta ll.
Late models with OBD II comp uters have sophisticated stra tegies to
detect severely ma lfuncti o ning EGR.
H owever, this basic check w ill work o n
a ll vac uum-contro lled EGR systems.
Loca te the EGR va lve a nd if it has a
vac uum hose connecti o n, unplug it.
Run th e engine at idle, a nd connect a
sp are hose fr o m a source of engine vacuum o r use a ma nual vacuum pump
a nd a ppl y vac uum to the hose neck.
The engine sho uld slow significa ntl y,
pro ba bly even stall , if yo u ap pl y full
engin e vac uum (17 to 21 in .).
If there's no significa nt change in
engin e idle-in fact, if the engin e has
been idling ro ugh-the valve may be
sti ck ing open. Remove it a nd if you can
see a heavy acc umulatio n of deposits in
the port, a nd if it's a n exposed pin -type
va lve, clea n it with a wire brush (Fig. 4) .
If the end of the pi n is recessed in the
po rt, it ca n't be clea ned. Replace it.

Where To Get
Service Information

top-post a nd side-termina l-are subj ect
to co ntinu o us drain with the engine off,
to keep a live the memories of ma ny
computers (from powertra in to car
radio). Just a slight coat of corrosionperhaps too subtle to be visible-can
reduce battery charge. Disconnect the
ca ble terminals. On a top-post battery,
bru sh aro und the post and inside the
ca bl e termin al (Fig. 5) . If the post o r
ca ble terminal is badl y corroded,
replace it w ith a premium terminal, the
kind that often includes a ca ble secti on.
Forget the cheap screw-together terminals-they'll become severely corroded
and ca use more problems th an th ey
solve. With a side-termin al ba ttery,

Di agnosing fa ilures th a t
produce t ro uble codes, a nd
findin g o ut normal readings
for engin e sensors, is not subject to rul e of thumb procedu res. Yo u need the latest fac tory
di ag nosti c sequ ences a nd specifi cati o ns. Ve hicl e ma kers have Web sites
w ith t hi s serv ice in fo rma ti o n, a nd
yo u' ll be a ble to access the da ta for a
day a t a time. Ma ny sites cha rge fo r
thi s informa ti on-yo u can pay using
a credit ca rd. At present, Genera l
M oto rs in fo rm a ti o n is ava il a bl e a t
www. acdelco.co m (click o n ACD elco
TechConn ect ). O r yo u ca n get a
low-cost subscripti o n fr o m ww w.a llda ta .co m (a lea ding so urce fo r
p rofess io na ls, w ith infor m ati o n o n all
m a kes) . In additi o n, AutoZone offe rs
free sca n too l connecti o ns a nd rea do uts a t its sto res. ~

(Fig. 5) Clean the battery posts and cable clamps regularly.

BATTERY POST BRUSH

/

Battery Terminals
Clea n the battery terminals, then reinsta ll and tighten. Today's batteries-

92

ENGINE

EASY

Smoothing Out a Lumpy Idle

ea rful p edestri a ns glare at yo u
as they pass in front of yo ur
bumper at crosswa lks. O ut of
embarrass ment, yo u try to igno re
them by glancin g aro und no nch alantly, stroking yo ur hair as yo u look
in the rearview mirror or tuning the
radio. Mea nw hil e, th e size of your
right thigh is growing to Dan Jansen
proportions from th e force bein g
appli ed to th e brake peda l. Your
engine's idl e speed is surging up and
down, creating crescendos that
wo uld make Pavarotti proud :
WAAAAaaaah, WAAAAaaaah,
WAAAAaaaah! It's all yo u can do to
keep yo ur maniacal car from lurching
fo rwa rd into a laws ui t.
There are a number of ge ner ic
steps yo u ca n ta ke to see w hat's a iling
yo ur wheels. And if th ere ever was a
time to step bac k a nd remember the
ba sics, this is it.
Pop quiz: W h at is an interna l-combustion engin e?
It's basica ll y littl e more than an air
pump. T he more a ir that gets in, the
fas ter th e engine run s. And a irfl ow
contro ls idle. By a ll ow in g a certa in
volume of air to bypa ss the closed
throttle plate( s), idle rpm can be
maintained at a healthy leve l. Even to
accelerate, we don 't "step on the

F

SMOOTHING

OUT A LUMPY IDLE

gas," we "step on th e air " by opening
th e throttl e plate farth er. Fuel is add ed
a nan osecond later, in response to th e
grea ter inta ke a irfl ow.

(Fig. 1, left) Make sure all the clamps
sealing the intake duct are tight.
(Fig. 2, right) Pull back the intake duct
to check for hidden cracks underneath.

Check Your Intake Tract
If yo ur engine uses a remotely mounted

ho le still needs to be sealed, or else
dirt a nd debri s will find its way in . If
th e engine uses an airflow sensor, this
type of lea k tends to a udibl y revea l
itse lf w hen th e engine torq ues forwa rd on its mounts an d opens wid e
th e co nvo lute crack .
Th en th e engine gets an unmetered
gulp of a ir and revs up on its own.
The idle speed control may try to
ca tch the speed burst by closing down
the bypass chann el. Then, when th e
engin e ret urn s to its norm a l positio n
a nd th e convo lute crack closes, th e
idl e speed is too low. In res ponse, th e
idl e contro ls may open up the chann el
aga in to raise the idle. This scenari o
can turn into a cycling condition that
produces a lumpy, rolling idle.
If yo u don't mind gettin g yo ur
engin e ba y a littl e messy, anoth er
q ui ck way to go a bo ut chec kin g fo r
intake trac t and runner lea ks is to
simpl y spray carburetor cl ea ner
aro und co nnections and the inta ke
manifold w hile the engine is run n ing
(Fig. 3) . If yo u get an rpm change
w hen yo u spray, it mea ns the vapo rs

air filter in an a ir box, inspect everything fro m there back to the throttle
p late(s ). At the air box, check all hose
connecti ons and make sure the cl amps
are ti ght (Fig. 1) . Replace the air filter
if it's so dirty that light fro m a lOO-wa tt
bulb doesn't pass through the element.
Make sure the new one seats properl y
in the air box and that the cover sits
flu sh and cl amps down evenly. Follow
the intake tract toward the throttle
plate, tightening a ll the clamps as yo u
go. If there's an inline mass airflow
meter in the tract, take extra care to
examine its connections for leaks.
Big, convoluted rubber tubing-style
intake tracts are susceptible to developing cracks between the convolutes
on th e und erside of the tube. They' re
generall y not visible unl ess yo u remove
one end of the tube and bend it back to
get a good look below (Fig. 2) . If the
engi ne control s meas ure airflow by
mea ns of a manifold abso lute pressure (MAP) sensor, this type of leak
sho uldn't affect idle q ua lity. But the

93

a re gettin g in so mehow. So yo u have
to pl ay spy to find th e lea k. Don't
sp ray nea r the d istributo r-if yo u
h ave o ne-beca use th ere's a cha nce
the solven t wi ll ignite a nd leave yo u
minu s yo ur eye brows and nose ha ir.

Keep Your Bore Clean
When yo u get to the last clamp a t the
throttle bore, unscrew it a nd remove the
intake tract. Take a look inside t he bore
w ith a fl as hlight. If the muck is so thick
that it's a wo nder the throttle plate can
move at a ll , you've found a major cause
of your lumpy idle. In addition to the
idle air-bypass chann el, a sma ll amount
of a ir must be a ble to pass aro und the
throttle plate itself. When blowby
vapors fwm the pev system (a nd EGR
exhaust gases) sludge up the bore over
time, the idle a ir-bypass functi on is seriouslyaffected.
Steal an o ld too thbrush from yo ur
kids (so yo ur w ife doesn't b low a gasket) a nd pick up some nonca ustic
fu el-i nj ecti o n intake cl ea ner at a n
a uto parts store. W it h t he engin e off,

spray some cleane r in th e bore and
start sc rubbin g w ith the too thbru sh.
Pay pa rti c ul ar a ttenti o n to th e circ um ferent ia l area where the th rottle
pl a te sits w hen closed. Also clean
both sid es of the plate and its edges.
If th e externally mounted idl e airbypass va lve is easil y removed a nd its
c ha nn e l eas il y accessed, tr y to get
c lea ner to pass thro ug h t he cha nn el
into the bore . Be sure to clea n the
va lve 's pintle tip, too (Fig. 4) . (Also
see page 122.)

Wash Down the Residue
With th e bore a nd cha nnel clean, stick
t he intake trac t back o n a nd start t he
engin e. If the engin e does n't use a n a irfl ow meter, yo u ca n pull the tract off
w ith th e engine run ning a nd spra y
so me more cleaner in the bore to was h
down the res idu e. Goose the throttle a
coup le of tim es. Then tighten the
clamp a nd let th e motor idle so tha t
the engin e- ma nage ment system ca n
re lea rn th e parameters necessa ry for
increased throttle p late a ir bypass.

(Fig. 3) Spray carb cleaner around the
throttle bore to find air leaks.

If yo ur engine does use an a irflow
meter, it' ll probably sta ll w hen yo u
pu ll the intake tract off the bore. Get it
started aga in a nd just pull th e end of
the rubber t ract bac k a bit w ith o ne o r
two fin gers to spray some more cl ea ner
down in the bore . T he engine wi ll
stumbl e for a second , but tha t's okay.
Whatever yo u do, don't spray the
clea ner into the tract before the a irfl ow
meter. Yo u co uld da mage t he meter.
Sing le- a nd dual -p o int inj ectio n
thro ttl e bo di es typ ica ll y don't sludge
up much beca use th ey're up top o n

HOW IT WORKS

Engine Management
An automotive computerized enginemanagement system works like any
computer as it controls idle speed. The
central processing unit relies on various inputs to calculate necessary outputs. On modern motors, however, the
inputs to the processor, or powertrain
control module (PCM) , are called sensors. The outputs are called actuators.
And the PCM is programmed to control
the actuators under any condition that
the sensors deem necessary.
Key sensory inputs of most enginemanagement systems include engine
speed, coolant temperature, crankshaft position, intake airflow, manifold
vacuum, throttle position and exhaust oxygen content.
Many systems go further, factoring in such inputs as
camshaft position, barometric pressure, intake air temperature, detonation detection, EGR valve position,
misfire detection, engine-oil temperature, power-steering pressure, air-conditioning pressures, gear-lever
position, vehicle speed, automatic-transmission-fluid

94

: ?

J

POWERTRAIN
CONTROL MODULE

----c:::=-_~ IDLE SPEED CONTROLLER

/

AIR
FILTER

EVAPORATIVE
EMISSIONS CANISTER
temperature, catalytic converter efficiency, system voltage and others.
Key actuators on many systems include the fuel injectors, idle speed control motor, EGR valve, evaporative
canister purge, ignition coil timing and dwell (saturation
time), torque converter clutch, smog pump diverter valve,
cooling fan, alternator output and fuel pump.

ENGINE

th e engin e and rcv vapors flow in
be low them. H owever, if the plate(s)
looks rea ll y d irty, it's okay to hi t it
w ith so me c lea ne r. JU St be careful not
to drown th e fuel inj ector sitting
di rect ly above the p late.
Assuming no o ne has ever p layed
w ith th e ba se idl e settings (the screw
may be sea led) and there's nothing
wrong w ith th e powertra in contro l
mod ul e's programm ing (th e malfunction indicator lamp has never illumi nated), th at covers the bas ic idle controls. Un less the ma nufacturer has
issued a softwa re upd ate, today's
engine-m anage ment systems are
sma rt eno ugh to take it from he re and
co ntinu e to pro vid e a smooth, ca refree idl e until the nex t tim e th at t h rottl e bore has jan ito r ial need s.

Loaded to the Hilt
W hen yo u cons id er th e number of
be lt-dr iven accesso ries hangi ng off th e
typical engin e today, in add iti o n to a ll
th e mecha ni ca l a nd e lectr ica l loads,
it's a wond er th e pi sto ns ca n co ntinu e
pumping a t a ll. That's w hy some ve hi cles today have 120-amp a lternators
and 140-amp fuses.
In rainy, co ld weather at night,
yo ur a ltern ato r is worki ng overtime to
mak e eno ugh amperage to power
eve rythin g. Probl em is, it's a lso try in g
to sto p th e eng in e from turnin g. H ere's
wh ere yo ur idl e speed cont ro l rea ll y
shin es. As soo n as a ltern ator o utp ut
drops to a certa in leve l, the vo ltage

(Fig. 4) Pull the idle speed
controller out of its bore to
inspect the pintle tip, spring
and air channel.

BOTTOM SIDE OF
THROTTLE BODY

regulator does its thin g a nd
th e engin e- ma nagement
system sees the need for
in creased idl e rpm to keep
charging-system vo ltage
between 13 Y'2 a nd 15 vo lts.
If a signal gets lost
throu gh a shorr or an open
circu it or a n intermittent
conn ection, however, yo u' re likely to
ge t a lump y or just plain low idl e.
H ere's w here yo u rea ll y need the specifi c service manua l a nd w iring d iagra ms for th e veh icle, beca use t here
are too man y variati o ns in form and
function to discuss these systems in
general terms. Some simple things yo u
can do, however, incl ud e visua ll y
checkin g for corroded-and even
burned-conn ections a t th e a ltern ator
a nd battery terminals. Eyeba ll the co nditi o n of a ll the fusibl e link s arou nd
the battery, a nd check for fo ul ed spark
plugs (Fig. 5) . Make sure the accessory
belt(s) is tigh t and unfra yed.
Every time the alc co mpressor
kick s in at idl e, engi ne speed wou ld
drop a co upl e hundred rpm were it
no t for th e idl e speed co ntro ls keeping
t hin gs at a n eve n kee l. H e re aga in ,
intermittent conn ections a nd a faulty
p ress ure sw itch or two cou ld ca use
th e climate contro l to cyc le in a nd
out. A low or co ntamin ated refr igera nt
charge might do the
sa me th i ng.
Somet im es
t he re's a p ress ure
sw itc h monitoring
your power stee ring
syste m, es pec iall y
o n 4-cylin de r
eng in es. Dur in g a
ti gh t pa r k in g- lo t
ma neuve r, when
power-steer i ng p ressure sk yrockets, the

engine contro ls ta ke the reins and
bump open th e idl e speed control
mo tor so yo ur eng in e doesn't sta ll or
bog down to th e po int of misfirin g. A
bad co nn ectio n o r leak a t th e sw itc h
wo ul d affect this system a nd possib ly
lead to a hunting id le. Periodic
power-steeri ng-system fl ushes go a
long way toward preventing clogged
switc hes a nd ori fi ces.
An eng in e w ith hi gh mil eage that's
tired and worn o ut may not pu ll a
healthy vac uum o f 18 to 20 in. H g at
idle (c losed t hro ttl e pl a te) anymore.
That means t he MAP se nsor w ill
always read t he engi ne as under load
(low vacu um=hi gh vo ltage ) and-just
doin g its job-inform th e powertrain
computer to add more fuel. Whe n the
oxygen se nso r picks up the ri ch mi xture in th e ex ha ust strea m, it wi II ca II
for a lea ner mi xture. Commo n strategy is to o pen t he id le a ir-bypass va lve
to let some more a ir in. Bur an engin e
that's just o n th e borderline of w heezing may intermittentl y "loosen up,"
leadi ng to a ro ll er coaster idl e. It ma y
have troub le breathing w hen co ld , but
once warm-with expa nded pi ston
rin gs, gaskets a nd th e like- show a
perfectl y hea lt hy intake vac uum.
What it a ll bo il s do w n to is tha t
there's a w ho le lot more than just a
carburetor 's throttl e stop screw controllin g yo ur engin e's idl e speed th ese
da ys . Si mpl y und ersta nding th e system , howeve r, is ha lf t he battle
toward fi ndin g a nd fi x ing the offending troub lema ker. ~

(Fig. 5) Fouled spark plugs can lead to misfiring at idle. They
can be cleaned and regapped or simply replaced.

SMOOTHING

OUT A LUMPY

IDLE

95

DIFFICULT

Replacing Your Water Pump
chroni ca ll y low leve l, p erhaps?) ca n
open up the working space and
reduce flow, as ca n co rrosion from
weak antifreeze in th e coo lant mix .

: :::::-:- ..... . :... ;;., .

..

-,,-

......... ·;0·.·.-...

.... .... .

ombing down the interstate,
yo u glance at the odometer and
realize yo u've just reached an
automotive mil estone: 100,000 miles
with no major repa irs. Time was a car
th at had passed its bell y over that
much rea l estate was considered pretty
much used up, but yo urs still run s
grea t and loo ks practica ll y new. Amazing how tec hnol ogy has advanced.
Then yo u notice th e temp erature
ga uge . H o ly smo kes-pegged! You
put it in neutra l, coast off onto the
sho uld er and shut her dow n. T here's
that ma ple-sy ru p-sp ilI ed-o n-th e-radia tor o dor aga in-yo u've sme ll ed it
before, but fi led it under " things to
think about later. " Sooner wo uld 've
been better-no w yo u're wa lking.

B

Seal Deal
The biggest change in water pump
design occ urred decades ago when the
spring-loa ded mechanica l sea l was
adopted . Howevel; its rubber parts
may di sintegrate if the engine overheats, and its po lished sea ling faces can
L
ear and wa rp if the engin e is run dry.

96

A~

(Fig. 1) Wet liquid seeping from the
weep hole signifies the end of the service life of the seals in your pump.

Typ ica ll y, pumps wi ll sta rt leak ing ca tas trophica ll y shortl y after a boi l-over.
Thi s kind of failure can be wo rse
th a n it so und s. Besides the vastl y
exp ensive internal engine damage
that runni'ng without coolant ma y
cause, a leak ing sea l can wash away
th e shaft bearing's lubricant, perhaps
res ultin g in a se ized shaft, and a fl yin g fa n o r belt pu ll ey ca n destroy the
radiator o r even dent th e hood.
So, leakage is th e o . 1 fa ilure.
o ise is seco nd, and is always indicati ve of a termin a l condition. While
service litera ture on water pumps
often will show a pictu re of a badly
eroded impell er th at contributes to
over hea tin g, tec hnicians say that's not
as co mm o n as it once was. Another
poss ibl e prob lem with the sa me conseq uences is an impell er th at 's come
loose from its shaft. Erosion of the
inside surfaces of the pump chamber
caused by cav itati on (a weak cap or a

Evidence Gathering
If yo u start to smell the distinctive
odor of engine coolant, or you notice
that th e level in the overflow bottl e is
droppin g rapidly, it's time for a careful exa m. (If yo u're lucky, it may be
just a leaky hose conn ectio n, but loo k
the radiator over, too. If the smell is
strong in th e passenger compartment
and th e w indshield tends to steam up ,
thin k abo ut the heater core. In cases
w here no ne of the above is the culprit,
better check o ut the water pump. )
First, use an inspection mirror a nd
a good li ght to view the vent ho le
th at's at th e bottom of the pump casting's nose (Fig. 1) . Or, support the
fro nt of the car safel y on jackstand s
and look up fro m underneath. All
sea ls are supposed to wee p sl ightl y (a
littl e coo la nt is needed to lu be the
faces), but dri ps mea n yo u'd better go
shopp in g for an estimate.
Next, grasp the fan or wa ter pump
pull ey a nd see if it rocks from side to
side. If there's anything but slight
movem ent, the bearing is on its way
o ut. Also, yo u can remove the belt
and see how the bearing feels as yo u
rotate the pump shaft (Fig. 2) .
Roughness isn't acceptable.
A low- fl ow situation that results in
hot running ca n be hard to diagnose .
Drain the leve l down to the top of the
radiator tubes, get the engine hot, and
th en shut it off for 10 minutes and let
it heat soak to make sure th e thermostat is wide open. Now, fire it up aga in
and run it at 3000 rpm. On Ja panese
cars usin g the radi ator fill neck on th e
top tank, look down into it w ith a
flashlight and yo u should see strong
circ ul atio n (Fig. 3) . Another p ossibility is to sq ueeze the upper hose to fee l

ENGINE

:w.>.-- - CHECK FOR PLAY

.. ; .....

"

.:',.:

.

.....

:.:~~ .

. .,', .. :
~

..

,- '

WEEP HOLE

(Fig. 2) Almost any radial play in the water pump
shaft is grounds for immediate pump replacement before
something fails.

for flow, bu t that's pretty su bjective.
Unfortunately, there's no good way for
the do-it- yo urselfer to differenti a te a
weak pump from a clogged rad iator.

Major Undertaking?
On some front-w heel drives the job is a
horro r sto ry. Make sure YO ll res ist the
temptati o n to get into thi s repa ir if

(Fig. 3) With the engine warm enough to open the
thermostat, but not hot enough to pressurize the system,
look for vigorous flow at 3000 rpm.

yo u' re not p repared to invest the time
requ ired. Find o ut the flat-rate hours
by ask ing a loca l garage owner or
dea ler service manager. It's a job that
could take severa l hours, depending on
wha t yo u dri ve, particularly if the
pump is recessed into the engine block.
T he first steps in removing a ny
water pump are to let t he engin e coo l

off com plete ly, a nd t hen dra in the
coo ling sys tem by ei th er openin g th e
rad iator petcock or d isco nn ectin g the
botto m radiator hose a nd remov ing
engi ne coo lan t dra in p lugs . Next, do
whatever is necessary to remove t he
accessory dri ve belts. If t he car has a
lo ngitudin a ll y mo unted engin e as
fo un d in every rwd a nd so me front-

HOW IT WORKS

Water Pump Shaft Seals
Two perfectly flat rings, one stationary and the other
rotating with the pump shaft, are pressed together by
means of a coil spring. The rings may be made of carbon
or may be ceramic, phenolic, porous bronze, cast iron,
etc., in any combination. This allows only enough seepage to keep the elements lubricated. It has a weak link,
however, in the form of its rubber parts-the bellows that
seals the spring and the rubber seat cup between the
rotating element and the shaft. If the engine is ever run
dry, the temperature of the pump is apt to rise far
beyond what the rubber can survive, and a leak occurs.
Another possibility is warpage of the sealing elements,
also from overheating.
There's conflicting evidence on whether silicates and
phosphates from antifreeze, or other hard particles such
as casting core sand, can actually damage the seal faces.
Engineers have told us the ' running clearance is way too
small to admit solids of any appreciable diameter.
Since cars are lasting longer than they used to, and
since we've become such a litigious society, carmakers
are working harder than ever to make water pumps last.
After all, when a pump goes you've got to get out and
walk, which exposes you to dangers that horrify auto
company lawyers.

So, there has been a push for water pump seals that
will rarely, if ever, fail. One design that looks promising is
from Michael Ostrowski and John Crane International,
the leading supplier of conventional water pump seals.
Called the Advanced Metal Diaphragm seal , it uses a
flexible stainless steel diaphragm that acts as both the
spring and the bellows, and incorporates an improved
method of mounting the seal faces.

J
REPLACING YOUR WATER

PUMP

97

(Fig. 4) This is an easy one, because
it's near the top. Your job would be a
lot tougher if the pump were near the
bottom .

th e sea m open or you ' ll make a nick
ley. Can yo u guess the possible misthat the gasket may not sea l.
take ? Think a bout direction : The serPumps sea l aga inst th e engin e o r
pentin e belt might dr ive the impeller in
backing p la te with a gas ket, an 0the opposite directi o n from that of the
dri ve rs, rem ove th e a ir shro ud s (in
ring o r RTV sili cone. Get th e ma ting
V-belt, so you cou ld end up in stalling a
so me cases, the ra di ator, too), a nd
su rface cl ean w ith a sc raper.
pump tha t runs backward, ca using a
then the fan a nd its clutch, w hich bo lt
If yo u mu st use silicone sea ler,
seemingly incurable o verheating situato the front of th e water pump shaft.
use o ne ra ted for a utom o ti ve use .
tion. Make sure yo u get exactl y
Novv you can start on the pump by
It should a lso be
the ri ght part, and compare the
disconnecting the hoses. Those for the
labe led low-vo la tilit y.
impell ers. Also, heed that routing
hea ter w ill proba bl y be stubbo rn, so
O utgass in g fro m th e
di agra m (Fig. 5) .
yo u ma y need to split th ei r end s w ith
curing sea la nt ca n po iAfter evel'ything is buttoned
a utilit y knife (if th ey' re lo ng eno ug h,
son oxygen se nso rs-so
up , fi gure o ut ho w much
you mi ght be ab le to trim th em off
lea ve th e ba thtub ca ulk
coo la nt your system ho lds.
square and reuse them ).
w ith yo ur plum bing too ls.
Thi s should be in your
Ex tract the pump-to-engine bolts
We shou ld menti o n a
owner's m a nual, or in the
and keep them and any brackets th ey
po tentia l pro bl em. Suppose
shop manual. Using the
retain in strict order or you 'll regret it
yo u're in stalling a water
a ppropriate manufacat assemb ly. Th ere m ay be hidden
pump o n a ca r with a se rpenturer's coo la nt, add ha lf
bo lts, so ta ke a loo k at a d iagra m.
tine belt. Engin es on man y
that a mo unt a nd t hen top
Th e pump sho uld co me off with a . o lder models were equ ip ped
off w ith water. This wi ll
good tu g (Fig. 4) . If not, ma ke sure
w ith a regul ar ribbed or Vgive yo u a 50-50 mix.
(Fig. 5) Vehicles with
you didn't miss any bolts, and then
belt, but the water pump
Be sure to follo w the
serpentine belts have a
tap on the inlet or outlet neck with a
for the old model ma y fit
procedure for
service
belt routing diagram
mallet or a block of wood and a ha mphysica ll y o n the new o ne,
bleeding the air bubbles
under the hood somemer. Don't use a screwdri ver to pry
if yo u cha nge over the pu lwhere. Read and obey.
out of the system. tI

98

ENGINE

-

ODERATE

Curing a Clicking Starter

Y

O U tw ist tb e ignitio n key to
sta rt yo ur engine, a nd in stead
of the syncopated w hirling of a
cran king sta rter and crankshaft, yo u
hear a click or a series of c harreriike
c li cks. Th e engin e t ha t sta rted eve ry
d ay for so lo ng is not go in g to starr
toda y. T im e to hitch a rid e to wo rk . If
it's a weeke nd , yo u get the cha nce to
find out why yo ur ve hicl e has died
and fi x the prob lem before Monday
mornll1 g.
Th a t cli ckin g noi se is from e ither
th e starte r so lenoid o r the re lay. Th e
so leno id is part of the sta rter. Typ ica ll y it has a terminal for a thick
power feed w ire fr o m th e ba rre ry
(Fig. 1), and a thinn er terminal fo r
the current supp ly w ire ro a sw itching
m echan ism in the soleno id. The rela y
is a remote ly mo unted sw itc hing

CURING

A CLICKING

STARTER

d ev ice between starter a nd ba tter y
t hat contro ls either the thi ck power
feed or the thinner electrical feed to
the so leno id 's sw itch termin a l.
Th e first step (a lthou gh a t thi s
point it do es n't tell yo u th e roo t
ca use) is to find o ut w he re th e c li ck is
co min g fro m. If you have a helper
turn the ig niti o n key to start, yo u' ll be
a ble to trace th e underh ood click . If it
comes fro m the starter, yo ur probl em
is in t he so leno id.
Ford a nd C hrys ler produ cts ma y
have a relay in th e circu it. If th e so lenoid isn't t he so ucce of t he cl ick, tracing th e so und sho uld ta ke yo u to th e
relay o n t hose mo dels.
Even after yo u know what pa rt is
click ing, begin yo ur real di agnosis a t
the batter y. If the barrery top has a n
"eye" indi cator (actuall y a battery

(Fig. 1) Loose or corroded starter
cables can cause enough voltage drop
to cause a clicking, intermittent connection. Clean with a wire brush and
then rinse with warm water.

h ydromete r th at in d icates th e state of
charge), recharge if th e in dicator is
bl ack. If it's g reen, it's got a no rmal
charge. If it's ye ll ow, ge t a new batter y
beca use the electro lyte is too low.
Th ere's no indica tor eye? Con nect
a vo ltm eter ac r oss th e ba ttery te rmina ls (pos itive lead to posit ive termi na l, nega ti ve lead to nega tive termina l). If the meter rea d s und er 12.4 to
12.5 vo lts, it's borde rline or und erc ha rged (depending o n the des ign of
th e battery). R echa rge it for th e da y.
Batteries do run dow n as a res ult of a
temporary series of operating condi-

99

(Fig. 2) Check for voltage drop
between battery post and starter
terminal while a helper cranks
the engine. Up to 0.50 volt is
acceptable.
tions (lots of short trips, for
exampl e), but if the pro blem
recurs, yo u' ll ha ve to check
ch arging system o utp ut and th e
poss ibility of a sho rt circuit.
If th e rea din g is 12.7 to 12.9
volts, th at's a good starting
point. After a recharge, operate
the head lamps fo r 15 seconds
to remove what is call ed the
" surface charge. " Th e m eter
reading sho uld not drop more
tb a n a bo ut 0.2 volt.
The rea din g is o kay? H ave a
helper turn th e igniti on key to
start, and in 15 seconds, rea d
the meter. If it's below 9.5
volts, th e battery may not be
strong eno ugh. Profess ionals have
battery loa d testers to make sure.
Your alternative: If th e battery vo ltage
wa s no rm a l wh en you started, but is
low during th e attemp t to crank, tr y a
jumpsta rt. If th e engin e cran ks nor-

mall y w ith a boost, the battery probabl y is bad.

Corroded, Distorted Terminals
If th e engine still wo n't cran k, next
in spect the cables and their connec-

ti ons at both ends. If yo u see
corros ion o r a possibl y poor
conn ecti on, ma ke a voltage
d rop test (Fig. 2) . First, conn ect
th e vo ltmeter negative lead to
the battery ground terminal and
the positi ve lead to the engine
block, cl ose to the starter. With
th e key held in th e start pos iti o n, th e vo ltmeter should rea d
und er 0.5 vo lt. If it's 0.5 vo lt or
higher, the drop is excessive. In
fac t, if it's above 0.2 volt, tb at's
rea lly too high and co uld be a
contributor to the problem if
the battery is marginal. Perform
the sa me check with the power
feed side of the circuit (in thi s
case, connect th e voltmeter's
positi ve lea d to the battery, and
th e nega tive lea d to the starter 's
battery ca bl e terminal) .
Get a high rea ding? Repea t
the test, taking care to make co ntact at
the battery post o r side-terminal bolt,
not th e cable end. If th e vo ltage drop
now is within reason, the cable terminals are the problem. A simple clea ning
may be all th at's needed, but if a ca ble's

HOW IT WORKS

Starter Solenoids
A solenoid is an electromagnetic device that is capable
of doing work, and in some starters, it does two jobs.
1) It moves a plunger that makes electrical contact
between terminals for the battery and the starter motor,
so the motor turns. If that's all it does, it's really just a
switching device. 2) In some starters, the movement of
the plunger also pushes a linkage that moves the
starter's drive gear into mesh with the flywheel ring gear.
The solenoid has two wire coils. One is large, draws
a lot of current and produces a strong magnetic field.
That's enough to move the plunger. Once the plunger is in
pOSition (having completed the circuit and moved the
starter drive), the large coil is disconnected and the circuit for a small coil is completed. The small coil draws a
small amount of current and produces a weaker magnetic field-just enough to hold the coil in position. This
saves battery energy for the big job of cranking the
engine. If there isn't quite enough battery electrical pressure (voltage) to provide the current flow, however, the
plunger won't lock into position so the small coil can take

100

FIELD COIL

IGNITION
SWITCH

FUSIBLE
LINK

T

!--

BATTERY

I

....L

I

~

~

.

;u ••••• 

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