1The sensor is located in the upper section of
the inlet manifold (DOHC fuel-injection
engines) or the side of the plenum chamber
(V6 engines).
2To remove the sensor, first disconnect the
battery negative lead.
3Disconnect the sensor wiring plug by pulling
on the plug, not the wiring (see illustration).
4Unscrew the sensor from the inlet manifold
and remove it.
5Refitting is a reversal of removal, applying a
smear of sealant to the threads of the sensor
and tightening it to the specified torque.
1Fitted to 2.0 litre DOHC fuel-injected
engines,this sensor is located in the top of the
fuel rail.
2To remove the sensor, first disconnect the
battery negative lead, and to improve access,
disconnect the wiring plug from the air charge
temperature sensor (in the inlet manifold).
Disconnect the sensor wiring plug by pulling
on the plug, not the wiring.
3Disconnect the fuel temperature sensor
wiring plug, again pulling on the plug (see
illustration).
4Unscrew the sensor from the fuel rail and
remove it.
5Refitting is a reversal of removal, tightening
the sensor to the specified torque.1Fitted to DOHC fuel-injected engines and to
V6 engines with catalytic converters, this
sensor is located in the left-hand side of the
gearbox/transmission.
2To remove the sensor first disconnect the
battery negative lead.
3Firmly apply the handbrake then jack up the
vehicle and support it securely on axle stands
(see “Jacking”).
4Detach the sensor wiring connector from
the bracket, and separate the two halves of
the connector (see illustration).
5Unscrew the securing bolt, and withdraw
the wiring connector bracket, noting the
orientation.
6Withdraw the sensor from the
gearbox/transmission casing.
7Before refitting the sensor, examine the O-
ring, and renew if damaged or worn.
8Refitting is a reversal of removal, ensuring
that the wiring connector bracket is correctly
located.
1On DOHC fuel-injected engines, this sensor
is located on the right-hand side of the engine
compartment where it is mounted either on
the suspension turret or on the bulkhead (see
illustration). V6 engines have the sensormounted on the centre of the engine
compartment bulkhead.
2To remove the sensor first disconnect the
battery negative terminal.
3Remove the two sensor retaining screws
and carefully withdraw the sensor, taking care
not to strain the wiring.
4Disconnect the wiring plug from the sensor,
pulling on the plug not the wiring, then
disconnect the vacuum hose and remove the
sensor.
5Refitting is a reversal of removal.
28Manifold absolute pressure
(MAP) sensor - removal and
refitting
27Vehicle speed sensor -
removal and refitting
26Fuel temperature sensor -
removal and refitting
25Air charge temperature
sensor - removal and refitting
5•12Engine electrical systems
25.3 Disconnecting the air charge
temperature sensor wiring plug
28.1 Manifold Absolute Pressure (MAP)
sensor location - models equipped with a
catalytic converter
26.3 Disconnecting the fuel temperature
sensor wiring plug27.4 Vehicle speed sensor wiring plug
(arrowed)
procarmanuals.com
the door through the large cut-out. Further
displacement or removal of the foamrubber
sheet may be necessary.
7Refit in the reverse order to removal, noting
the following points:
a)Apply a little grease to the interior handle
rods where they pass through the plastic
bushes
b)When securing the interior handle, have
the locking lever in the “unlocked”
position, hold the assembly forwards as
far as itwill go and tighten the securing
screw
c)Check all functions before refitting the trim
panel.
Door weatherstrip
1Open the door and remove the weatherstrip
securing screw from the latch end. In the case
of the rear door, also remove the screw from
the hinge end.
2Carefully lift the latch end of the
weatherstrip and pull it off the door.
3Refit by reversing the removal operations,
using your palm to seat the weatherstrip.
Aperture weatherstrip
4Open the door. Remove the scuff plate
securing screws from the bottom of the door
aperture.
5Pull the old weatherstrip out of the door
aperture.
6Fit the new weatherstrip, starting at the
right-angled corner at the top. Fit the
weatherstrip to the other corners and bends,
leaving the straight sections until last.
7Refit the scuff, plate securing screws.
All models except Estate
1Disconnect the battery negative lead.
2Remove the tailgate interior trim panel,
which is secured by eleven screws.
3Remove the six nuts which secure the
tailgate handle. Remove the handle and
recover the gasket.
4Disconnect the tailgate lock switch multi-
plug. Release the switch locking tab and
remove the switch.
5Disconnect the operating rod from the lock
lever (see illustration). Extract the U-clip and
remove the lock barrel.
6Refit by reversing the removal operations.
Estate models
7The tailgate lock barrel can be removed and
refitted as described above, bearing in mind
the notes made in Section 8 when removing
the interior trim panels and noting that the lock
assembly is retained by two Torx bolts.1Open up the boot lid and remove the trim
panel from the inside of the lid.
2Unscrew the four boot lid exterior trim
retaining panel bolts (two situated on each
side of the lock) then carefully prise out the
nine panel retaining clips and remove the
panel from the boot lid.
3Undo the two lock barrel retaining nuts then
partially withdraw the barrel and disconnect the
wiring connector and lock operating rod from
the barrel. Remove the lock barrel from the lid.
4Undo the four lid lock retaining bolts then
withdraw the lock assembly from the boot lid,
disconnecting the central locking and warning
switch wiring plugs (see illustration).
5Refitting is a reversal of the removal
procedure tightening all retaining bolts
securely. On completion check the operation
of the boot lid lock and lock barrel before
refitting the trim panel.
1Disconnect the battery negative lead.
2Remove the tailgate interior trim panel,
which is secured by eleven screws.
3Unhook the operating rod from the tailgate
latch. Also disconnect the lock switch and
solenoid multi-plugs.4Remove the three bolts which secure the
tailgate latch. Remove the latch.
5Refit by reversing the removal operations.
1Open the tailgate and support it with a piece
of wood.
2Release the strut from its mountings by
raising the spring clips with a small
screwdriver, then pulling the strut off the ball-
stands. Do not raise the clips more than 4 mm
(0.16 in) if the strut is to be re-used.
3Do not attempt to dismantle a strut, and
dispose of it safely. It contains gas under
pressure.
4To refit a strut, position it over the ball-
studs. Push on each end in turn until it snaps
home.
1Open the fuel filler flap. Remove the key.
2Apply pressure to the lock barrel at the key
slot, using the thumb of one hand. With the
other hand insert a screwdriver into the cut-
out in the filler flap to release the lock barrel
retaining spring. As the spring is released,
thumb pressure will eject the lock barrel into
the petrol tank (see illustration).
3To refit, push the lock barrel into the flap
until the retaining spring clicks home.
Front door
1Open the door and remove the screws
which secure the front and rear edges of the
trim panel (see illustration).
2Remove the two screws from under the
covers on the door pocket. Unclip and remove
the pocket.
3On models with electrically-operated
windows and mirrors, prise out and disconnect
the window and mirror switches. The window
switch multi-plugs on the driver’s side are
22Door interior trim panel -
removal and refitting
21Fuel filler lock barrel -
removal and refitting
20Tailgate strut - removal and
refitting
19Tailgate latch assembly -
removal and refitting
18Boot lid lock barrel - removal
and refitting
17Tailgate lock barrel - removal
and refitting
16Door weatherstrip - removal
and refitting
Bodywork and fittings 12•7
12
17.5 Operating rod (arrowed) connected to
tailgate lock lever18.4 Boot lid lock retaining bolts (arrowed)
- Saloon models
21.2 Removing the fuel filler flap lock barrel
procarmanuals.com
Estate
7Note that when removing the rear window
wiper arm, it will be necessary to detach the
washer hose from the spindle prior to
removing the wiper arm retaining nut (see
illustration).
1Remove the windscreen wiper arms as
described in the previous Section.
2Undo the eight Torx screws which secure
the wiper motor and linkage to the bulkhead
(see illustrations).3Disconnect the multi-plug and remove the
motor and linkage (see illustration).
4The linkage arms can be removed by
levering them off the pivot pins.
5To remove the motor, undo the crank arm
nut and remove the three securing bolts (see
illustration). The motor cover can then be
removed. A defective motor must be renewed.
6Refit by reversing the removal operations.
Before refitting the wiper arms, switch the
wipers on and then off so that the motor takes
up the “parked” position.
1Remove the rear wiper arm from the spindle.
2Open the tailgate and remove the interior
trim panel, which is secured by eleven screws.
3Remove the three bolts which secure the
wiper motor bracket to the tailgate (see
illustration). Also remove the screw which
secures the earth tag. Disconnect the wiring
plug and remove the motor and bracket.
4The bracket can be unbolted from the motor
if wished. No spare parts for the motor are
available.
5Commence refitting by offering the motor
and bracket to the tailgate. Secure the
assembly with the three bolts, then reconnect
the wiring and secure the earth tag.
6Switch on the ignition and operate the rear
wiper control briefly so that the motor stops in
the “parked” position.7Refit the wiper arm and blade. Wet the
window and operate the rear wiper control
again to check the function of the motor.
8Switch off the ignition and refit the tailgate
interior trim panel.
Windscreen and rear washer jets are
removed simply by prising or pulling them
from their locations (see illustration).
Headlight washer jets can be unclipped from
their holders after disconnection of the high
pressure hose from the jet.
To remove a washer pump, first syphon out
the contents of the reservoir. Disconnect the
wiring and the hose from the pump, then pull
the pump out of its grommet in the reservoir.
Renew the grommet if necessary when
refitting the pump.
1The fuel tank sender unit, EEC IV module
and speedometer sender unit are not peculiar
to the fuel computer. Their removal and
refitting procedures are given in Chapter 4,
Chapter 5 and this Chapter respectively.
26Fuel computer components -
removal and refitting
25Windscreen, rear window and
headlight washer components
- removal and refitting
24Rear window wiper motor -
removal and refitting
23Windscreen wiper motor and
linkage - removal and refitting
Body electrical system 13•17
13
23.2a Two screws (arrowed) in the front of
the motor . . .23.2b . . . three screws around the right-
hand spindle . . .23.2c . . . and two screws on the left.
Eighth screw is midway between the spindles
23.5 Undo the crank arm nut and the three
bolts (arrowed)
23.3 Disconnecting the wiper motor multi-
plug
24.3 Three bolts secure the rear wiper
motor (two arrowed)25.1 A windscreen washer jet prised out of
its location in the bonnet
procarmanuals.com
The vehicle owner who does his or her own maintenance according
to the recommended service schedules should not have to use this
section of the manual very often. Modern component reliability is such
that, provided those items subject to wear or deterioration are
inspected or renewed at the specified intervals, sudden failure is
comparatively rare. Faults do not usually just happen as a result of
sudden failure, but develop over a period of time. Major mechanical
failures in particular are usually preceded by characteristic symptoms
over hundreds or even thousands of miles. Those components which
do occasionally fail without warning are often small and easily carried
in the vehicle.With any fault-finding, the first step is to decide where to begin
investigations. Sometimes this is obvious, but on other occasions, a
little detective work will be necessary. The owner who makes half a
dozen haphazard adjustments or replacements may be successful in
curing a fault (or its symptoms), but will be none the wiser if the fault
recurs, and ultimately may have spent more time and money than was
necessary. A calm and logical approach will be found to be more
satisfactory in the long run. Always take into account any warning
signs or abnormalities that may have been noticed in the period
preceding the fault - power loss, high or low gauge readings, unusual
smells, etc - and remember that failure of components such as fuses or
REF•5Fault Finding
Engine1
m mEngine fails to rotate when attempting to start
m mStarter motor turns engine slowly
m mEngine rotates, but will not start
m mEngine difficult to start when cold
m mEngine difficult to start when hot
m mStarter motor noisy or excessively-rough in engagement
m mEngine starts, but stops immediately
m mEngine idles erratically
m mEngine misfires at idle speed
m mEngine misfires throughout the driving speed range
m mEngine hesitates on acceleration
m mEngine stalls
m mEngine lacks power
m mEngine backfires
m mOil pressure warning light illuminated with engine running
m mEngine runs-on after switching off
m mEngine noises
Cooling system2
m
mOverheating
m mOvercooling
m mExternal coolant leakage
m mInternal coolant leakage
m mCorrosion
Fuel and exhaust systems3
m
mExcessive fuel consumption
m mFuel leakage and/or fuel odour
m mExcessive noise or fumes from exhaust system
Clutch4
m
mPedal travels to floor - no pressure or very little resistance
m mClutch fails to disengage (unable to select gears)
m mClutch slips (engine speed increases, with no increase in vehicle
speed)
m mJudder as clutch is engaged
m mNoise when depressing or releasing clutch pedal
Manual gearbox5
m
mNoisy in neutral with engine running
m mNoisy in one particular gear
m mDifficulty engaging gears
m mJumps out of gear
m mVibration
m mLubricant leaks
Automatic transmission6
m
mFluid leakage
m mTransmission fluid brown, or has burned smellm mGeneral gear selection problems
m mTransmission will not downshift (kickdown) with accelerator fully
depressed
m mEngine will not start in any gear, or starts in gears other than Park
or Neutral
m mTransmission slips, shifts roughly, is noisy, or has no drive in
forward or reverse gears
Propeller shaft7
m
mClicking or knocking noise on turns (at slow speed on full-lock)
m mVibration when accelerating or decelerating
Final drive and driveshafts8
m
mExcessive final drive noise
m mOil leakage from final drive
m mGrating, knocking or vibration from driveshafts
Braking system9
m
mVehicle pulls to one side under braking
m mNoise (grinding or high-pitched squeal) when brakes applied
m mExcessive brake pedal travel
m mBrake pedal feels spongy when depressed
m mExcessive brake pedal effort required to stop vehicle
m mJudder felt through brake pedal or steering wheel when braking
m mPedal pulsates when braking hard
m mBrakes binding
m mRear wheels locking under normal braking
Suspension and steering systems10
m
mVehicle pulls to one side
m mWheel wobble and vibration
m mExcessive pitching and/or rolling around corners, or during braking
m mWandering or general instability
m mExcessively-stiff steering
m mExcessive play in steering
m mLack of power assistance
m mTyre wear excessive
Electrical system11
m
mLights inoperative
m mIgnition/no-charge warning light remains illuminated with engine
running
m mIgnition/no-charge warning light fails to come on
m mBattery will not hold a charge for more than a few days
m mInstrument readings inaccurate or erratic
m mHorn inoperative, or unsatisfactory in operation
m mWindscreen/tailgate wipers inoperative, or unsatisfactory in
operation
m mWindscreen/tailgate washers inoperative, or unsatisfactory in
operation
m mElectric windows inoperative, or unsatisfactory in operation
m mCentral locking system inoperative, or unsatisfactory in operation
Introduction
procarmanuals.com
Engine misfires throughout the driving speed range
m mFuel filter choked (Chapter 1).
m mFuel pump faulty, or delivery pressure low (Chapter 4).
m mFuel tank vent blocked, or fuel pipes restricted (Chapter 4).
m mVacuum leak at the throttle body, inlet manifold or associated hoses
(Chapter 4).
m mWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
m mFaulty spark plug HT leads (Chapter 5).
m mDistributor cap cracked or tracking internally (Chapter 5).
m mFaulty ignition coil (Chapter 5).
m mUneven or low cylinder compressions (Chapter 2).
m mFuel injection system fault (Chapter 4).
Engine hesitates on acceleration
m
mWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
m mVacuum leak at the throttle body, inlet manifold or associated hoses
(Chapter 4).
m mFuel injection system fault (Chapter 4).
Engine stalls
m
mVacuum leak at the throttle body, inlet manifold or associated hoses
(Chapter 4).
m mFuel filter choked (Chapter 1).
m mFuel pump faulty, or delivery pressure low (Chapter 4).
m mFuel tank vent blocked, or fuel pipes restricted (Chapter 4).
m mFuel injection system fault (Chapter 4).
Engine lacks power
m
mFuel filter choked (Chapter 1).
m mFuel pump faulty, or delivery pressure low (Chapter 4).
m mUneven or low cylinder compressions (Chapter 2).
m mWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
m mVacuum leak at the throttle body, inlet manifold or associated hoses
(Chapter 4).
m mFuel injection system fault (Chapter 4).
m mBrakes binding (Chapters 1 and 10).
m mClutch slipping (Chapter 6).
Engine backfires
m
mVacuum leak at the throttle body, inlet manifold or associated hoses
(Chapter 4).
m mFuel injection system fault (Chapter 4).
Oil pressure warning light illuminated with engine
running
m mLow oil level, or incorrect oil grade (Chapter 1).
m mFaulty oil pressure sensor (Chapter 2).
m mWorn engine bearings and/or oil pump (Chapter 2).
m mExcessively high engine operating temperature (Chapter 3).
m mOil pressure relief valve defective (Chapter 2).
m mOil pick-up strainer clogged (Chapter 2).
Note:Low oil pressure in a high-mileage engine at tickover is not
necessarily a cause for concern. Sudden pressure loss at speed is far
more significant. In any event, check the gauge or warning light sender
before condemning the engine.
Engine runs-on after switching off
m mExcessive carbon build-up in engine (Chapter 2).
m mExcessively high engine operating temperature (Chapter 3).
Engine noises
Pre-ignition (pinking) or knocking during acceleration or
under load
m mIgnition timing incorrect/ignition system fault (Chapters 1 and 5).
m mIncorrect grade of spark plug (Chapter 1).
m mIncorrect grade of fuel (Chapter 1).
m mVacuum leak at throttle body, inlet manifold or associated hoses
(Chapter 4).
m mExcessive carbon build-up in engine (Chapter 2).
m mFuel injection system fault (Chapter 4).
Whistling or wheezing noises
m
mLeaking inlet manifold or throttle body gasket (Chapter 4).
m mLeaking exhaust manifold gasket (Chapter 4).
m mLeaking vacuum hose (Chapters 4 and 10).
m mBlowing cylinder head gasket (Chapter 2).
Tapping or rattling noises
m
mWorn valve gear, timing chain, camshaft or hydraulic tappets
(Chapter 2).
m mAncillary component fault (water pump, alternator, etc) (Chapters 3,
5, etc).
Knocking or thumping noises
m mWorn big-end bearings (regular heavy knocking, perhaps less under
load) (Chapter 2).
m mWorn main bearings (rumbling and knocking, perhaps worsening
under load) (Chapter 2).
m mPiston slap (most noticeable when cold) (Chapter 2).
m mAncillary component fault (water pump, alternator, etc) (Chapters 3,
5, etc).
REF•7Fault Finding
2Cooling system
Overheating
m
mAuxiliary drivebelt broken or incorrectly adjusted (Chapter 1).
m mInsufficient coolant in system (Chapter 1).
m mThermostat faulty (Chapter 3).
m mRadiator core blocked, or grille restricted (Chapter 3).
m mElectric cooling fan or thermostatic switch faulty (Chapter 3).
m mViscous-coupled fan faulty (Chapter 3).
m mIgnition timing incorrect, or ignition system fault (Chapters 1 and 5).
m mInaccurate temperature gauge sender unit (Chapter 3).
m mAirlock in cooling system (Chapter 3).
Overcooling
m
mThermostat faulty (Chapter 3).
m mInaccurate temperature gauge sender unit (Chapter 3).
External coolant leakage
m
mDeteriorated or damaged hoses or hose clips (Chapter 1).
m mRadiator core or heater matrix leaking (Chapter 3).
m mPressure cap faulty (Chapter 3).
m mWater pump internal seal leaking (Chapter 3).
m mWater pump-to-block seal leaking (Chapter 3).
m mBoiling due to overheating (Chapter 3).
m mCore plug leaking (Chapter 2).
Internal coolant leakage
m
mLeaking cylinder head gasket (Chapter 2).
m mCracked cylinder head or cylinder block (Chapter 2).
Corrosion
m
mInfrequent draining and flushing (Chapter 1).
m mIncorrect coolant mixture or inappropriate coolant type (Chapter 1).
procarmanuals.com
REF•8
Pedal travels to floor - no pressure or very little
resistance
m m
Badly stretched or broken cable (Chapter 6).m
mStripped pawl on pedal (Chapter 6).m
mBroken clutch release bearing or arm (Chapter 6).m
mBroken diaphragm spring in clutch pressure plate (Chapter 6).
Clutch fails to disengage (unable to select gears)
m m
Cable free play excessive (Chapter 6).m
mClutch driven plate sticking on gearbox input shaft splines (Chapter 6).m
mClutch driven plate sticking to flywheel or pressure plate (Chapter 6).m
mFaulty pressure plate assembly (Chapter 6).m
mClutch release mechanism worn or incorrectly assembled (Chapter 6).
Clutch slips (engine speed increases, with no
increase in vehicle speed)
m m
Clutch driven plate linings excessively worn (Chapter 6).m
mClutch driven plate linings contaminated with oil or grease (Chapter 6).m
mFaulty pressure plate or weak diaphragm spring (Chapter 6).
Judder as clutch is engaged
m m
Clutch driven plate linings contaminated with oil or grease (Chapter 6).m
mClutch driven plate linings excessively worn (Chapter 6).m
mFaulty or distorted pressure plate or diaphragm spring (Chapter 6).m
mWorn or loose engine or gearbox mountings (Chapter 2).m
mClutch driven plate hub or gearbox input shaft splines worn
(Chapter 6).
Noise when depressing or releasing clutch pedal
m m
Worn clutch release bearing (Chapter 6).m
mWorn or dry clutch pedal pivot (Chapter 6).m
mFaulty pressure plate assembly (Chapter 6).m
mPressure plate diaphragm spring broken (Chapter 6).m
mBroken clutch driven plate cushioning springs (Chapter 6).
Excessive fuel consumption
m
mAir filter element dirty or clogged (Chapter 1).
m mFuel injection system fault (Chapter 4).
m mIgnition timing incorrect or ignition system fault (Chapters 1 and 5).
m mBrakes binding (Chapter 10).
m mTyres under-inflated (Chapter 1).
Fuel leakage and/or fuel odour
m
mDamaged fuel tank, pipes or connections (Chapters 1 and 4).
Excessive noise or fumes from exhaust system
m
mLeaking exhaust system or manifold joints (Chapters 1 and 4).
m mLeaking, corroded or damaged silencers or pipe (Chapters 1 and 4).
m mBroken mountings causing body or suspension contact (Chapter 4).
Fault Finding
4Clutch
5Manual gearbox
Noisy in neutral with engine running
m m
Input shaft bearings worn (noise apparent with clutch pedal
released, but not when depressed) (Chapter 7A).*
m mClutch release bearing worn (noise apparent with clutch pedal
depressed, possibly less when released) (Chapter 6).
Noisy in one particular gear
m m
Worn, damaged or chipped gear teeth (Chapter 7A).*
Difficulty engaging gears
m m
Clutch fault (Chapter 6).m
mWorn or damaged gear linkage (Chapter 7A).m
mWorn synchroniser units (Chapter 7A).*
Jumps out of gear
m m
Worn or damaged gear linkage (Chapter 7A).m
mWorn synchroniser units (Chapter 7A).*m
mWorn selector forks (Chapter 7A).*
Vibration
m m
Lack of oil (Chapter 1).m
mWorn bearings (Chapter 7A).*
Lubricant leaks
m m
Leaking oil seal (Chapter 7A).m
mLeaking housing joint (Chapter 7A).*
*Although the corrective action necessary to remedy the symptoms
described is beyond the scope of the home mechanic, the above
information should be helpful in isolating the cause of the condition, so
that the owner can communicate clearly with a professional mechanic.
6Automatic transmission
Note:Due to the complexity of the automatic transmission, it is difficult
for the home mechanic to properly diagnose and service this unit. For
problems other than the following, the vehicle should be taken to a
dealer service department or automatic transmission specialist.
Fluid leakage
m m
Automatic transmission fluid is usually deep red in colour. Fluid
leaks should not be confused with engine oil, which can easily be
blown onto the transmission by air flow.
m mTo determine the source of a leak, first remove all built-up dirt and
grime from the transmission housing and surrounding areas, using a
degreasing agent or by steam-cleaning. Drive the vehicle at low speed,
so that air flow will not blow the leak far from its source. Raise and
support the vehicle, and determine where the leak is coming from. The
following are common areas of leakage:
a)Fluid pan ( transmission “sump”).
b)Dipstick tube (Chapter 1).
c)Transmission-to-fluid cooler fluid pipes/unions (Chapter 7B).
3Fuel and exhaust systems
procarmanuals.com
REF•12Glossary of Technical Terms
A
ABS (Anti-lock brake system)A system,
usually electronically controlled, that senses
incipient wheel lockup during braking and
relieves hydraulic pressure at wheels that are
about to skid.
Air bag An inflatable bag hidden in the
steering wheel (driver’s side) or the dash or
glovebox (passenger side). In a head-on
collision, the bags inflate, preventing the
driver and front passenger from being thrown
forward into the steering wheel or windscreen.
Air cleanerA metal or plastic housing,
containing a filter element, which removes
dust and dirt from the air being drawn into the
engine.
Air filter elementThe actual filter in an air
cleaner system, usually manufactured from
pleated paper and requiring renewal at regular
intervals.
Allen keyA hexagonal wrench which fits into
a recessed hexagonal hole.
Alligator clipA long-nosed spring-loaded
metal clip with meshing teeth. Used to make
temporary electrical connections.
AlternatorA component in the electrical
system which converts mechanical energy
from a drivebelt into electrical energy to
charge the battery and to operate the starting
system, ignition system and electrical
accessories.
Ampere (amp)A unit of measurement for the
flow of electric current. One amp is the
amount of current produced by one volt
acting through a resistance of one ohm.
Anaerobic sealerA substance used to
prevent bolts and screws from loosening.
Anaerobic means that it does not require
oxygen for activation. The Loctite brand is
widely used.
AntifreezeA substance (usually ethylene
glycol) mixed with water, and added to a
vehicle’s cooling system, to prevent freezing
of the coolant in winter. Antifreeze also
contains chemicals to inhibit corrosion and
the formation of rust and other deposits that
would tend to clog the radiator and coolant
passages and reduce cooling efficiency.
Anti-seize compoundA coating that
reduces the risk of seizing on fasteners that
are subjected to high temperatures, such as
exhaust manifold bolts and nuts.
AsbestosA natural fibrous mineral with great
heat resistance, commonly used in the
composition of brake friction materials.Asbestos is a health hazard and the dust
created by brake systems should never be
inhaled or ingested.
AxleA shaft on which a wheel revolves, or
which revolves with a wheel. Also, a solid
beam that connects the two wheels at one
end of the vehicle. An axle which also
transmits power to the wheels is known as a
live axle.
AxleshaftA single rotating shaft, on either
side of the differential, which delivers power
from the final drive assembly to the drive
wheels. Also called a driveshaft or a halfshaft.
BBall bearingAn anti-friction bearing
consisting of a hardened inner and outer race
with hardened steel balls between two races.
BearingThe curved surface on a shaft or in a
bore, or the part assembled into either, that
permits relative motion between them with
minimum wear and friction.
Big-end bearingThe bearing in the end of
the connecting rod that’s attached to the
crankshaft.
Bleed nippleA valve on a brake wheel
cylinder, caliper or other hydraulic component
that is opened to purge the hydraulic system
of air. Also called a bleed screw.
Brake bleedingProcedure for removing air
from lines of a hydraulic brake system.
Brake discThe component of a disc brake
that rotates with the wheels.Brake drumThe component of a drum brake
that rotates with the wheels.
Brake liningsThe friction material which
contacts the brake disc or drum to retard the
vehicle’s speed. The linings are bonded or
riveted to the brake pads or shoes.
Brake padsThe replaceable friction pads
that pinch the brake disc when the brakes are
applied. Brake pads consist of a friction
material bonded or riveted to a rigid backing
plate.
Brake shoeThe crescent-shaped carrier to
which the brake linings are mounted and
which forces the lining against the rotating
drum during braking.
Braking systemsFor more information on
braking systems, consult the Haynes
Automotive Brake Manual.
Breaker barA long socket wrench handle
providing greater leverage.
BulkheadThe insulated partition between
the engine and the passenger compartment.
CCaliperThe non-rotating part of a disc-brake
assembly that straddles the disc and carries
the brake pads. The caliper also contains the
hydraulic components that cause the pads to
pinch the disc when the brakes are applied. A
caliper is also a measuring tool that can be set
to measure inside or outside dimensions of an
object.
CamshaftA rotating shaft on which a series
of cam lobes operate the valve mechanisms.
The camshaft may be driven by gears, by
sprockets and chain or by sprockets and a
belt.
CanisterA container in an evaporative
emission control system; contains activated
charcoal granules to trap vapours from the
fuel system.
CarburettorA device which mixes fuel with
air in the proper proportions to provide a
desired power output from a spark ignition
internal combustion engine.
CastellatedResembling the parapets along
the top of a castle wall. For example, a
castellated balljoint stud nut.
CastorIn wheel alignment, the backward or
forward tilt of the steering axis. Castor is
positive when the steering axis is inclined
rearward at the top.
Canister
Brake bleeding
Bearing
Air filter
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REF•13Glossary of Technical Terms
Catalytic converterA silencer-like device in
the exhaust system which converts certain
pollutants in the exhaust gases into less
harmful substances.
CirclipA ring-shaped clip used to prevent
endwise movement of cylindrical parts and
shafts. An internal circlip is installed in a
groove in a housing; an external circlip fits into
a groove on the outside of a cylindrical piece
such as a shaft.
ClearanceThe amount of space between
two parts. For example, between a piston and
a cylinder, between a bearing and a journal,
etc.
Coil springA spiral of elastic steel found in
various sizes throughout a vehicle, for
example as a springing medium in the
suspension and in the valve train.
CompressionReduction in volume, and
increase in pressure and temperature, of a
gas, caused by squeezing it into a smaller
space.
Compression ratioThe relationship between
cylinder volume when the piston is at top
dead centre and cylinder volume when the
piston is at bottom dead centre.
Constant velocity (CV) jointA type of
universal joint that cancels out vibrations
caused by driving power being transmitted
through an angle.
Core plugA disc or cup-shaped metal device
inserted in a hole in a casting through which
core was removed when the casting was
formed. Also known as a freeze plug or
expansion plug.
CrankcaseThe lower part of the engine
block in which the crankshaft rotates.
CrankshaftThe main rotating member, or
shaft, running the length of the crankcase,
with offset “throws” to which the connecting
rods are attached.
Crocodile clipSee Alligator clipDDiagnostic codeCode numbers obtained by
accessing the diagnostic mode of an engine
management computer. This code can be
used to determine the area in the system
where a malfunction may be located.
Disc brakeA brake design incorporating a
rotating disc onto which brake pads are
squeezed. The resulting friction converts the
energy of a moving vehicle into heat.
Double-overhead cam (DOHC)An engine
that uses two overhead camshafts, usually
one for the intake valves and one for the
exhaust valves.
Drivebelt(s)The belt(s) used to drive
accessories such as the alternator, water
pump, power steering pump, air conditioning
compressor, etc. off the crankshaft pulley.
DriveshaftAny shaft used to transmit
motion. Commonly used when referring to the
axleshafts on a front wheel drive vehicle.
Drum brakeA type of brake using a drum-
shaped metal cylinder attached to the inner
surface of the wheel. When the brake pedal is
pressed, curved brake shoes with friction
linings press against the inside of the drum to
slow or stop the vehicle.
EEGR valveA valve used to introduce exhaust
gases into the intake air stream.
Electronic control unit (ECU)A computer
which controls (for instance) ignition and fuel
injection systems, or an anti-lock braking
system. For more information refer to the
Haynes Automotive Electrical and Electronic
Systems Manual.
Electronic Fuel Injection (EFI)A computer
controlled fuel system that distributes fuel
through an injector located in each intake port
of the engine.
Emergency brakeA braking system,
independent of the main hydraulic system,
that can be used to slow or stop the vehicle if
the primary brakes fail, or to hold the vehicle
stationary even though the brake pedal isn’t
depressed. It usually consists of a hand lever
that actuates either front or rear brakes
mechanically through a series of cables and
linkages. Also known as a handbrake or
parking brake.EndfloatThe amount of lengthwise
movement between two parts. As applied to a
crankshaft, the distance that the crankshaft
can move forward and back in the cylinder
block.
Engine management system (EMS)A
computer controlled system which manages
the fuel injection and the ignition systems in
an integrated fashion.
Exhaust manifoldA part with several
passages through which exhaust gases leave
the engine combustion chambers and enter
the exhaust pipe.
F
Fan clutchA viscous (fluid) drive coupling
device which permits variable engine fan
speeds in relation to engine speeds.
Feeler bladeA thin strip or blade of hardened
steel, ground to an exact thickness, used to
check or measure clearances between parts.
Firing orderThe order in which the engine
cylinders fire, or deliver their power strokes,
beginning with the number one cylinder.
Flywheel A heavy spinning wheel in which
energy is absorbed and stored by means of
momentum. On cars, the flywheel is attached
to the crankshaft to smooth out firing
impulses.
Free playThe amount of travel before any
action takes place. The “looseness” in a
linkage, or an assembly of parts, between the
initial application of force and actual
movement. For example, the distance the
brake pedal moves before the pistons in the
master cylinder are actuated.
FuseAn electrical device which protects a
circuit against accidental overload. The typical
fuse contains a soft piece of metal which is
calibrated to melt at a predetermined current
flow (expressed as amps) and break the
circuit.
Fusible linkA circuit protection device
consisting of a conductor surrounded by
heat-resistant insulation. The conductor is
smaller than the wire it protects, so it acts as
the weakest link in the circuit. Unlike a blown
fuse, a failed fusible link must frequently be
cut from the wire for replacement.Catalytic converter
Crankshaft assembly
Accessory drivebelts
Feeler blade
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