radiator JAGUAR XJ6 1997 2.G Owner's Manual

of these sensors and their corresponding
ECU-controlled relays are not contained
within EFI components, but are located
throughout the engine compartment. For
further information regarding the ECU and its
relationship to the engine electrical and
ignition system, see Chapter 6.
12 Electronic Fuel Injection
(EFI) system- check
2
1Check the earth wire connections for
tightness. Check all wiring and electrical
connectors that are related to the system.
Loose electrical connectors and poor grounds
can cause many problems that resemble
more serious malfunctions.
2Check to see that the battery is fully
charged, as the control unit and sensors
depend on an accurate supply voltage in
order to properly meter the fuel.
3Check the air filter element - a dirty or
partially blocked filter will severely impede
performance and economy (see Chapter 1).
4If a blown fuse is found, renew it and see if
it blows again. If it does, search for a shorted
wire in the harness related to the system.
5Check the air intake duct from the MAF
sensor to the intake manifold for leaks, which
will result in an excessively lean mixture. Also
check the condition of the vacuum hoses
connected to the intake manifold.
6Remove the air intake duct from the throttle
body and check for carbon and residue build-
up. If it’s dirty, clean with aerosol carburettor
cleaner (make sure the can says it’s safe for
use with oxygen sensors and catalytic
converters) and a toothbrush.
7With the engine running, place a
stethoscope against each injector, one at a
time, and listen for a clicking sound, indicating
operation (see illustration).8If there is a problem with an injector,
purchase a special injector test light (noid
light) and refit it into the injector electrical
connector (see illustration). Start the engine
and make sure that each injector connector
flashes the noid light. This will test for the
proper voltage signal to the injector.Caution:
If the engine will not start and the noid
light indicates that each injector is
receiving the proper signal, there is a good
possibility that the injector(s) is stuck open
and allowing fuel into the combustion
chamber in excessive amounts. If the spark
plugs are fouled, detach the primary (low
voltage) wires from the ignition coil, disable
the fuel pump by removing the fuel pump
relay (see Section 2), remove the spark plugs
and crank the engine over. If fuel sprays from
the spark plug holes, the engine is flooded
and the fuel must be removed from the
combustion chambers.
9With the engine OFF and the fuel injector
electrical connectors disconnected, measure
the resistance of each injector (see
illustration). Each injector should measure
about 2.0 to 3.0 ohms. If not, the injector is
probably faulty.10The remainder of the system checks
should be left to a Jaguar service department
or other qualified repair workshop, as there is
a chance that the control unit may be
damaged if not performed properly.
13 Electronic Fuel Injection
(EFI) system- component
check and renewal
3
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. See
the Warning in Section 2.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
Throttle body
Check
1Verify that the throttle linkage operates
smoothly.
2Start the engine, detach each vacuum hose
and, using your finger, check the vacuum at
each port on the throttle body with the engine
at idle and above idle. The vacuum available
from the throttle body is ported. Raise the
engine rpm and watch as vacuum increases.
It may be necessary to use a vacuum gauge.
Refer to Chapter 2B for additional information
concerning vacuum checks.
Renewal
Warning: Wait until the engine is
completely cool before
beginning this procedure.
3Detach the cable from the negative terminal
of the battery (see the Cautionat the
beginning of this Section).
4Drain the radiator (see Chapter 1).
4•10 Fuel and exhaust systems
12.9 Using an ohmmeter, measure the
resistance across both terminals
of the injector
3261 Jaguar XJ6 12.7 Use a stethoscope or a screwdriver to determine if the
injectors are working properly - they should make a steady
clicking sound that rises and falls with engine speed changes
12.8 Refit the “noid” light into the fuel injector electrical
connector and check to see that it blinks with the engine running

3261 Jaguar XJ6
11
Chapter 11
Bodywork and fittings
Body - maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Body repair - major damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Body repair - minor damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Bonnet - removal, refitting and adjustment . . . . . . . . . . . . . . . . . . . . 10
Bonnet and boot lid support struts - removal and refitting . . . . . . . . 9
Bonnet release latch and cable - removal and refitting . . . . . . . . . . . 11
Boot lid - removal, refitting and adjustment . . . . . . . . . . . . . . . . . . . 16
Boot lid latch and lock cylinder - removal and refitting . . . . . . . . . . . 17
Bumpers - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Centre console - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 24
Cowl cover - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Dashboard trim panels - removal and refitting . . . . . . . . . . . . . . . . . 26
Door - removal, refitting and adjustment . . . . . . . . . . . . . . . . . . . . . . 19
Door latch, lock cylinder and handles - removal and refitting . . . . . . 20
Door trim panel - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 18Door window glass - removal and refitting . . . . . . . . . . . . . . . . . . . . 22
Door window glass regulator - removal and refitting . . . . . . . . . . . . . 21
Front spoiler - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 13
Front wing - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Hinges and locks - maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Instrument cluster housing - removal and refitting . . . . . . . . . . . . . . 25
Outside mirrors - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 23
Radiator grille - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 12
Seats - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Steering column cover - removal and refitting . . . . . . . . . . . . . . . . . 27
Upholstery and carpets - maintenance . . . . . . . . . . . . . . . . . . . . . . . 4
Vinyl trim - maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Windscreen and fixed glass - replacement . . . . . . . . . . . . . . . . . . . . 8
11•1
Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321
1 General information
These models feature a “unibody”
construction, using a floor pan with front and
rear frame side rails which support the body
components, front and rear suspension
systems and other mechanical components.
Certain components are particularly vulnerable
to accident damage and can be unbolted and
repaired or replaced. Among these parts are
the body mouldings, bumpers, front wings,
bonnet and boot lids and all glass.
Only general body maintenance practices
and body panel repair procedures within the
scope of the do-it-yourselfer are included in
this Chapter.
2 Body- maintenance
1
1The condition of your vehicle’s body is very
important, because the resale value depends
a great deal on it. It’s much more difficult to
repair a neglected or damaged body than it is
to repair mechanical components. The hidden
areas of the body, such as the wheel wells,
the frame and the engine compartment, areequally important, although they don’t require
as frequent attention as the rest of the body.
2Once a year, or every 12,000 miles, it’s a
good idea to have the underside of the body
steam cleaned. All traces of dirt and oil will be
removed and the area can then be inspected
carefully for rust, damaged brake lines, frayed
electrical wires, damaged cables and other
problems. The front suspension components
should be greased after completion of this job.
3At the same time, clean the engine and the
engine compartment with a steam cleaner or
water soluble degreaser.
4The wheel wells should be given close
attention, since undercoating can peel away
and stones and dirt thrown up by the tyres
can cause the paint to chip and flake, allowing
rust to set in. If rust is found, clean down to
the bare metal and apply an anti-rust paint.
5The body should be washed about once a
week. Wet the vehicle thoroughly to soften the
dirt, then wash it down with a soft sponge and
plenty of clean soapy water. If the surplus dirt
is not washed off very carefully, it can wear
down the paint.
6Spots of tar or asphalt thrown up from the
road should be removed with a cloth soaked
in solvent.
7Once every six months, wax the body and
chrome trim. If a chrome cleaner is used to
remove rust from any of the vehicle’s plated
parts, remember that the cleaner also removes
part of the chrome, so use it sparingly.
3 Vinyl trim- maintenance
1
Don’t clean vinyl trim with detergents,
caustic soap or petroleum-based cleaners.
Plain soap and water works just fine, with a
soft brush to clean dirt that may be ingrained.
Wash the vinyl as frequently as the rest of the
vehicle.
After cleaning, application of a high quality
rubber and vinyl protectant will help prevent
oxidation and cracks. The protectant can also
be applied to weather-stripping, vacuum lines
and rubber hoses (which often fail as a result
of chemical degradation) and to the tyres.
4 Upholstery and carpets-
maintenance
1
1Every three months remove the carpets or
mats and clean the interior of the vehicle
(more frequently if necessary). Vacuum the
upholstery and carpets to remove loose dirt
and dust.
2Leather upholstery requires special care.
Stains should be removed with warm water
and a very mild soap solution. Use a clean,
damp cloth to remove the soap, then wipe

7Attach a piece of thin wire or string to the
end of the cables to help aid the refitting
process.
8Working in the engine compartment, pull
the cables and grommet out of the bulkhead
until you can see the wire or string. Ensure
that the new cable has a grommet attached
then remove the old cable from the wire or
string and replace it with the new cable.
9Working from passenger compartment pull
the wire or string back through the bulkhead.
10Refitting is the reverse of removal.Note:
Push on the grommet with your fingers from
the engine compartment to seat the grommet
in the bulkhead.
12 Radiator grille-
removal and refitting
1
1Using a Phillips screwdriver, detach the
right and left hand grille inserts from the grille
assembly (see illustration).Note: The grille
can be removed without removing the inserts,
but reaching the mounting screws from above
is quite difficult.
2Working through the grille insert openings,
remove the retaining screws securing both
ends of the grille frame (see illustration).
3Pull the grille frame forward and remove it
from the vehicle.
4Refitting is the reverse of removal.
13 Front spoiler-
removal and refitting
1
1Working on the left side of the vehicle,
remove the front spoiler lower cover (see
illustration).
2Remove the screws securing the front air
dam panels in the left and right wheel
openings (see illustration), then detach the
air dam panels from the vehicle. Note:It will
probably be necessary to turn the wheels to
the right and left for access to the screws.
3Detach the retaining bolts securing the
sides of the spoiler (see illustration).
4Working through the grille area of thespoiler, detach the retaining screws securing
the front of the spoiler (see illustration).
5Pull the spoiler forward and detach it from
the vehicle.
6Refitting is the reverse of removal.
14 Bumpers-
removal and refitting
1
1Detach the direction indicator and side
marker light assemblies from the bumper(s)
(see illustrations).
2Disconnect all wire harness connectors
attached to the bumper or light assemblies
that would interfere with removal.
Bodywork and fittings 11•5
11
12.1 Removing one side at a time, remove
the grille insert retaining screws (arrowed)
- tilt the top edge of the grille insert
forward, then lift up and out to remove it12.2 Working through the grille insert
openings, remove the retaining screws
from each edge of the grille frame
13.4 Working through the grille area of the
spoiler, remove the screws (arrowed)
retaining the front of the spoiler14.1a Depress the retaining clips on each
side of the side marker lamp assemblies,
then gently prise forward to remove it . . .14.1b . . . then detach the direction
indicator assemblies from the bumper in
the same manner
13.1 Working underneath the vehicle,
remove the screws (arrowed) securing the
front spoiler lower cover13.2 Working in the front wheel openings,
remove the screws (arrowed) securing the
front air dam panels13.3 The retaining bolts (arrowed)
securing the sides of the front spoiler are
located behind the bumper
3261 Jaguar XJ6

3Remove two bumper retaining bolts located
on the bottom side of the bumper (see
illustration). Pull the bumper assembly out
and away from the vehicle to remove it.
4Refitting is the reverse of removal.
15 Front wing-
removal and refitting
3
1Loosen the front wheel nuts. Raise the
vehicle, support it securely on axle stands and
remove the front wheel.
2Remove the front bumper assembly (see
Section 14).
3Remove the front spoiler (see Section 13).4Detach the inner wing splash shield (see
illustration).
5On 1988 and 1989 models, remove the
coolant overflow reservoir located behind the
splash shield (see Chapter 3).
6On models with round headlights, remove
the headlight bezel. On models with
composite headlights (1992 Vanden Plas, all
1993 and later models), remove the headlight
(see Chapter 12).
7Remove the wing mounting bolts and nuts
(see illustrations).
8Detach the wing. It’s a good idea to have an
assistant support the wing while it’s being
moved away from the vehicle to prevent
damage to the surrounding body panels.
9Refitting is the reverse of removal.
16 Boot lid- removal,
refitting and adjustment
2
Note:The boot lid is heavy and somewhat
awkward to remove and refit - at least two
people should perform this procedure.
Removal and refitting
1Open the boot lid and cover the edges of
the boot compartment with pads or cloths to
protect the painted surfaces when the lid is
removed.
2Disconnect any cables or wire harness
connectors attached to the boot lid that would
interfere with removal.
3Make alignment marks around the hinge
mounting bolts with a marking pen.
4While an assistant supports the boot lid,
remove the lid-to-hinge bolts on both sides
and lift it off(see illustration).
5Refitting is the reverse of removal. Note:
When refitting the boot lid, align the lid-to-
hinge bolts with the marks made during
removal.
Adjustment
6Fore-and-aft and side-to-side adjustment
of the boot lid is done by moving the bonnet in
relation to the hinge plate after loosening the
bolts or nuts.
7Scribe a line around the entire hinge plate
as described earlier in this section so you can
judge the amount of movement.
11•6 Bodywork and fittings
14.3 Remove the two retaining bolts from
the bottom of the bumper, then remove the
bumper from the vehicle15.4 Remove the bolts (arrowed) securing
the inner wing splash shield15.7a Detach the wing retaining bolts
(arrowed) at the front of the wing
15.7c Working in the wheel opening,
remove the wing-to-rocker panel bolt
(arrowed)
15.7d Remove the wing-to-door pillar bolt
(arrow; lower bolt not visible)15.7e Detach the bolts along the
top of the wing
3261 Jaguar XJ6
15.7b Remove the wing-to-radiator
support bolt (arrowed)
16.4 With the help of an assistant to hold
the boot lid, remove the retaining bolts and
lift off the boot lid

6If the voltage is 6 volts, the element is okay
(there is no break). If the voltage is 12 volts,
the element is broken between the centre
of the element and the positive end. If the
voltage is 0 volts the element is broken
between the centre of the element and earth.
7To find the break, place the voltmeter
positive lead against the defogger positive
terminal. Place the voltmeter negative lead
with the foil strip against the heating element
at the positive terminal end and slide it toward
the negative terminal end. The point at which
the voltmeter deflects from zero to several
volts is the point at which the heating element
is broken (see illustration).
Repair
8Repair the break in the element using a
repair kit specifically recommended for this
purpose.
9Prior to repairing a break, turn off the system
and allow it to cool off for a few minutes.
10Lightly buff the element area with fine
steel wool, then clean it thoroughly with
rubbing alcohol.
11Use masking tape to mask off the area
being repaired.
12Thoroughly mix the epoxy, following the
instructions provided with the repair kit.
13Apply the epoxy material to the slit in the
masking tape, overlapping the undamaged
area about 3/4-inch on either end (see
illustration).
14Allow the repair to cure for 24 hours before
removing the tape and using the system.
17 Headlights- renewal
1
Warning: Later models are
equipped with halogen gas-filled
headlight bulbs which are underpressure and may shatter if the surface is
damaged or the bulb is dropped. Wear eye
protection and handle the bulbs carefully,
grasping only the base whenever possible.
Do not touch the surface of the bulb with
your fingers because the oil from your skin
could cause it to overheat and fail
prematurely. If you do touch the bulb
surface, clean it with rubbing alcohol.
Sealed beam units
1Remove the radiator grille (see Chapter 11).
2Detach the headlight bezel trim cover (see
illustration).
3Remove the headlight bezel (see
illustrations).
4Remove the screws which secure the
retaining ring and withdraw the ring. Support
the light as this is done (see illustration).
Body electrical system 12•9
12
16.13 Apply masking tape to the inside of
the window at the damaged area, then
brush on the special conductive coating17.2 Remove the screws (arrowed) and
detach the headlight bezel trim cover
17.3a Remove the two retaining screws
at the top and the one in the grille opening
(arrowed)17.3b The retaining screw at the
outside lower corner can be accessed
from under the bumper
3261 Jaguar XJ6 16.5 To determine if a heating element has broken, check the
voltage at the centre of each element. If the voltage is 6-volts, the
element is unbroken; if the voltage is 12-volts, the element is
broken between the centre and the positive end. If there is no
voltage, the element is broken between the centre and earth
16.7 To find the break, place the voltmeter positive lead against
the heated window positive terminal, place the voltmeter negative
lead with the foil strip against the heating element at the positive
terminal end and slide it toward the negative terminal end -
the point at which the voltmeter reading changes abruptly is the
point at which the element is broken

5Pull the headlight out slightly and
disconnect the electrical connector from the
rear of the light, then remove the light from the
vehicle.
6To refit, position the new unit close enough
to connect the electrical connector. Make
sure that the numbers moulded into the lens
are at the top.
7Refit and tighten the retaining ring. Test the
headlight operation.
8The remainder of the refitting is the reverse
of removal.
Halogen gas-filled bulbs
9Disconnect the electrical connector from
the bulb assembly. Rotate the headlight bulb
connector 1/4-turn anti-clockwise (viewed
from the rear) (see illustration).
10Withdraw the bulb assembly from the
headlight housing.
11Without touching the glass with your bare
fingers (see the Warningat the start of the
Section), insert the new bulb assembly into
the headlight housing and rotate the bulb
socket 1/4-turn clockwise to refit it.
12Plug in the electrical connector and test
headlight operation.
18 Headlights- adjustment
5
Note:The following procedure is intended for
emergency use only, and we strongly
recommend that the headlight aim is only
checked using optical beam-setting
equipment. It is important that the headlights
are aimed correctly. If adjusted incorrectly
they could blind the driver of an oncoming
vehicle and cause a serious accident or
seriously reduce your ability to see the road.
The headlights should be checked for proper
aim every 12 months and any time a new
headlight is installed or front end body work is
performed.
1Adjustment should be made with the
vehicle sitting level, the petrol tank half-full
and no unusually heavy load in the vehicle.2Early models with sealed beam headlights
have four adjusting knobs protruding through
the backside of the radiator support. The
vertical (up and down) adjustment knobs are
located above the headlight and the horizontal
(left to right) adjusting knobs are located
below the headlight (see illustration).
3On later models with halogen bulbs,
adjustments are made in the same manner as
described in the previous step, except there
are only two adjusting knobs which tilt the
headlight housing to the desired angle.
4If the headlight housing has been replacedor the vehicle has suffered front-end damage,
refer to following procedure.
5This method requires a blank wall, masking
tape and a level floor.
6Position masking tape vertically on the wall
in reference to the vehicle centreline and the
centrelines of both headlights (see
illustration).
7Position a horizontal tape line in reference
to the centreline of all the headlights. Note:It
may be easier to position the tape on the wall
with the vehicle parked only a few inches
away.
12•10 Body electrical system
3261 Jaguar XJ618.2 The headlight horizontal
adjustment knob (A) is located at the
top of the headlight and the vertical
adjustment knob (B) is below the headlight
17.4 Loosen the retaining ring screws
(arrowed) a few turns - rotate the retaining
ring anti-clockwise to remove it17.9 Disconnect the electrical connector
and rotate the bulb assembly 1/4-turn
anti-clockwise
18.6 Headlight
adjustment details

8Adjustment should be made with the
vehicle parked 25 feet from the wall, sitting
level, the petrol tank half-full and no unusually
heavy load in the vehicle.
9Starting with the low beam adjustment,
position the high intensity zone so it is two
inches below the horizontal line and two
inches to the right of the headlight vertical
line. Adjustments are made by turning the
knobs located behind the headlight housings
(see illustration 18.2).
10With the high beams on, the high intensity
zone should be vertically centred with the
exact centre just below the horizontal line.
Note:It may not be possible to position the
headlight aim exactly for both high and low
beams. If a compromise must be made, keep
in mind that the low beams are the most used
and have the greatest effect on safety.
11Have the headlights adjusted by a dealer
service department or service station at the
earliest opportunity.
19 Headlight housing
(1992 to 1994 models)-
removal and refitting
1
Warning: These vehicles are
equipped with halogen gas-filled
headlight bulbs which are under
pressure and may shatter if the
surface is damaged or the bulb is dropped.
Wear eye protection and handle the bulbs
carefully, grasping only the base whenever
possible. Do not touch the surface of the
bulb with your fingers because the oil from
your skin could cause it to overheat and
fail prematurely. If you do touch the bulb
surface, clean it with rubbing alcohol.
1Remove the headlight bulb (Section 17).
2Remove the retaining nuts, detach the
housing and withdraw it from the vehicle (see
illustration).
3Refitting is the reverse of removal.
20 Horn- check and renewal
2
Check
Note:Check the fuses before beginning
electrical diagnosis.
1Disconnect the electrical connector from
the horn.
2To test the horn, connect battery voltage to
the two terminals with a pair of jumper wires.
If the horn doesn’t sound, renew it.
3If the horn does sound, check for voltage at
the terminal when the horn button is
depressed (see illustration). If there’s voltage
at the terminal, check for a bad earth at the
horn.
4If there’s no voltage at the horn, check the
relay (see Section 6). Note that most horn
relays are either the four-terminal or externally
earthed three-terminal type.
5If the relay is OK, check for voltage to the
relay power and control circuits. If either of the
circuits are not receiving voltage, inspect the
wiring between the relay and the fuse panel.
6If both relay circuits are receiving voltage,
depress the horn button and check the circuit
from the relay to the horn button for continuityto earth. If there’s no continuity, check the
circuit for an open. If the circuit is good, renew
the horn button.
7If there’s continuity to earth through the
horn button, check for an open or short in the
circuit from the relay to the horn.Renewal
8Remove the radiator grille inserts (see
Chapter 11).
9Disconnect the electrical connector and
remove the retaining nuts securing the horn
brackets (see illustration).
10Refitting is the reverse of removal.
21 Bulb renewal
1
Front direction indicator/rear
parking and side marker lights
1Remove the lens retaining screws and the
lens (see illustration).
2Push inward and rotate the bulb anti-
clockwise to remove it from the holder.
3Renew the bulb, refit the lamp lens and test
the bulb operation.
Body electrical system 12•11
12
20.9 Disconnect the electrical connector,
remove the retaining nuts (arrowed) - then
detach the horn(s)21.1 The front direction indicator/rear
parking and side marker light bulbs are
accessible after removing the lens screws
3261 Jaguar XJ6 19.2 Remove the headlight housing retaining nuts (arrowed) from
the backside of the radiator support
20.3 Check for power at the horn terminal with the horn button
depressed

3261 Jaguar XJ6
REF•14Fault finding
2 Fuel system
Engine surges while holding accelerator steady
m mIntake air leak (Chapter 4).
m mFuel pump faulty (Chapter 4).
m mLoose fuel injector harness connections (Chapters 4 and 6).
m mDefective ECU (Chapter 6).
Pinking or knocking engine sounds during
acceleration or uphill
m mIncorrect grade of fuel.
m mDistributor installed incorrectly (Chapter 5).
m mFuel injection system in need of adjustment (Chapter 4).
m mImproper or damaged spark plugs or wires (Chapter 1).
m mWorn or damaged distributor components (Chapter 5).
m mFaulty emission system (Chapter 6).
m mVacuum leak (Chapter 4).
m mFuel rail feed (inlet) hose has hardened, resulting in knocking noise
near dash (see Chapter 4).
Engine lacks power
m mIncorrect ignition timing (Chapter 5).
m mExcessive play in distributor shaft (Chapter 5).
m mWorn rotor, distributor cap or wires (Chapters 1 and 5).
m mFaulty or incorrectly gapped spark plugs (Chapter 1).
m mFuel injection system malfunctioning (Chapter 4).
m mFaulty coil (Chapter 5).
m mBrakes binding (Chapter 1).
m mAutomatic transmission fluid level incorrect (Chapter 1).
m mFuel filter clogged and/or impurities in the fuel system (Chapter 1).
m mEmission control system not functioning properly (Chapter 6).
m mLow or uneven cylinder compression pressures (Chapter 2).
Engine rattles at start-up
m
mFailure of upper timing chain tensioner (Chapter 2).
Engine backfires
m
mEmissions system not functioning properly (Chapter 6).
m mIgnition timing incorrect (Chapter 1).
m mFaulty secondary ignition system (cracked spark plug insulator,
faulty plug leads, distributor cap and/or rotor) (Chapters 1 and 5).
m mFuel injection system malfunctioning (Chapter 4).
m mVacuum leak at fuel injector(s), intake manifold or vacuum hoses
(Chapter 4).
Engine stalls
m mIdle speed incorrect (Chapter 1).
m mFuel filter clogged and/or water and impurities in the fuel system
(Chapter 1).
m mDistributor components damp or damaged (Chapter 5).
m mFaulty emissions system components (Chapter 6).
m mFaulty or incorrectly gapped spark plugs (Chapter 1).
m mFaulty spark plug leads (Chapter 1).
m mVacuum leak in the fuel injection system, intake manifold or
vacuum hoses (Chapter 4).
Engine runs with oil pressure light on
m mLow oil level (Chapter 1).
m mIdle rpm too low (Chapter 1).
m mShort in wiring circuit (Chapter 12).
m mFaulty oil pressure sending unit (Chapter 2).
m mWorn engine bearings and/or oil pump (Chapter 2).
Engine diesels (continues to run)
after switching off
m mIdle speed too high (Chapter 4).
m mExcessive engine operating temperature (Chapter 3).
m mIncorrect fuel octane grade.
Excessive fuel consumption
m
mDirty or clogged air filter element (Chapter 1).
m mIncorrectly set ignition timing (Chapter 5).
m mEmissions system not functioning properly (Chapter 6).
m mFuel injection internal parts worn or damaged (Chapter 4).
m mLow tyre pressure or incorrect tyre size (Chapter 1).
Fuel leakage and/or fuel odour
m
mLeak in a fuel feed or vent line (Chapter 4).
m mTank overfilled.
m mFuel injector internal parts excessively worn (Chapter 4).
3 Cooling system
Overheating
m
mInsufficient coolant in system (Chapter 1).
m mWater pump drivebelt defective or out of adjustment (Chapter 1).
m mRadiator core blocked or grille restricted (Chapter 3).
m mThermostat faulty (Chapter 3).
m mRadiator cap not maintaining proper pressure (Chapter 3).
m mIgnition timing incorrect (Chapter 5).
Overcooling
m
mFaulty thermostat (Chapter 3).
External coolant leakage
m
mDeteriorated/damaged hoses; loose clamps (Chapters 1 and 3).
m mWater pump seal defective (Chapters 1 and 3).
m mLeakage from radiator core or manifold tank (Chapter 3).
m mEngine drain or water jacket core plugs leaking (Chapter 2).
m mHoses behind water pump leaking (Chapter 3).
Internal coolant leakage
m
mLeaking cylinder head gasket (Chapter 2).
m mCracked cylinder bore or cylinder head (Chapter 2).
Coolant loss
m
mToo much coolant in system (Chapter 1).
m mCoolant boiling away because of overheating (Chapter 3).
m mInternal or external leakage (Chapter 3).
m mFaulty radiator cap (Chapter 3).
Poor coolant circulation
m
mInoperative water pump (Chapter 3).
m mRestriction in cooling system (Chapters 1 and 3).
m mWater pump drivebelt defective/out of adjustment (Chapter 1).
m mThermostat sticking (Chapter 3).
1 Engine (continued)

3261 Jaguar XJ6
REF•18Glossary 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

3261 Jaguar XJ6
REF•20Glossary of technical terms
GGapThe distance the spark must travel in
jumping from the centre electrode to the side
electrode in a spark plug. Also refers to the
spacing between the points in a contact
breaker assembly in a conventional points-
type ignition, or to the distance between the
reluctor or rotor and the pickup coil in an
electronic ignition.
GasketAny thin, soft material - usually cork,
cardboard, asbestos or soft metal - installed
between two metal surfaces to ensure a good
seal. For instance, the cylinder head gasket
seals the joint between the block and the
cylinder head.
GaugeAn instrument panel display used to
monitor engine conditions. A gauge with a
movable pointer on a dial or a fixed scale is an
analogue gauge. A gauge with a numerical
readout is called a digital gauge.
HHalfshaftA rotating shaft that transmits
power from the final drive unit to a drive
wheel, usually when referring to a live rear
axle.
Harmonic balancerA device designed to
reduce torsion or twisting vibration in the
crankshaft. May be incorporated in the
crankshaft pulley. Also known as a vibration
damper.
HoneAn abrasive tool for correcting small
irregularities or differences in diameter in an
engine cylinder, brake cylinder, etc.
Hydraulic tappetA tappet that utilises
hydraulic pressure from the engine’s
lubrication system to maintain zero clearance
(constant contact with both camshaft and
valve stem). Automatically adjusts to variation
in valve stem length. Hydraulic tappets also
reduce valve noise.
IIgnition timingThe moment at which the
spark plug fires, usually expressed in the
number of crankshaft degrees before the
piston reaches the top of its stroke.
Inlet manifoldA tube or housing with
passages through which flows the air-fuel
mixture (carburettor vehicles and vehicles with
throttle body injection) or air only (port fuel-
injected vehicles) to the port openings in the
cylinder head.
JJump startStarting the engine of a vehicle
with a discharged or weak battery by
attaching jump leads from the weak battery to
a charged or helper battery.
LLoad Sensing Proportioning Valve (LSPV)A
brake hydraulic system control valve that
works like a proportioning valve, but also
takes into consideration the amount of weight
carried by the rear axle.
LocknutA nut used to lock an adjustment
nut, or other threaded component, in place.
For example, a locknut is employed to keep
the adjusting nut on the rocker arm in
position.
LockwasherA form of washer designed to
prevent an attaching nut from working loose.
MMacPherson strutA type of front
suspension system devised by Earle
MacPherson at Ford of England. In its original
form, a simple lateral link with the anti-roll bar
creates the lower control arm. A long strut - an
integral coil spring and shock absorber - is
mounted between the body and the steering
knuckle. Many modern so-called MacPherson
strut systems use a conventional lower A-arm
and don’t rely on the anti-roll bar for location.
MultimeterAn electrical test instrument with
the capability to measure voltage, current and
resistance.
NNOxOxides of Nitrogen. A common toxic
pollutant emitted by petrol and diesel engines
at higher temperatures.
OOhmThe unit of electrical resistance. One
volt applied to a resistance of one ohm will
produce a current of one amp.
OhmmeterAn instrument for measuring
electrical resistance.
O-ringA type of sealing ring made of a
special rubber-like material; in use, the O-ring
is compressed into a groove to provide the
sealing action.
Overhead cam (ohc) engineAn engine with
the camshaft(s) located on top of the cylinder
head(s).Overhead valve (ohv) engineAn engine with
the valves located in the cylinder head, but
with the camshaft located in the engine block.
Oxygen sensorA device installed in the
engine exhaust manifold, which senses the
oxygen content in the exhaust and converts
this information into an electric current. Also
called a Lambda sensor.
PPhillips screwA type of screw head having a
cross instead of a slot for a corresponding
type of screwdriver.
PlastigageA thin strip of plastic thread,
available in different sizes, used for measuring
clearances. For example, a strip of Plastigage
is laid across a bearing journal. The parts are
assembled and dismantled; the width of the
crushed strip indicates the clearance between
journal and bearing.
Propeller shaftThe long hollow tube with
universal joints at both ends that carries
power from the transmission to the differential
on front-engined rear wheel drive vehicles.
Proportioning valveA hydraulic control
valve which limits the amount of pressure to
the rear brakes during panic stops to prevent
wheel lock-up.
RRack-and-pinion steeringA steering system
with a pinion gear on the end of the steering
shaft that mates with a rack (think of a geared
wheel opened up and laid flat). When the
steering wheel is turned, the pinion turns,
moving the rack to the left or right. This
movement is transmitted through the track
rods to the steering arms at the wheels.
RadiatorA liquid-to-air heat transfer device
designed to reduce the temperature of the
coolant in an internal combustion engine
cooling system.
RefrigerantAny substance used as a heat
transfer agent in an air-conditioning system.
R-12 has been the principle refrigerant for
many years; recently, however, manufacturers
have begun using R-134a, a non-CFC
substance that is considered less harmful to
the ozone in the upper atmosphere.
Rocker armA lever arm that rocks on a shaft
or pivots on a stud. In an overhead valve
engine, the rocker arm converts the upward
movement of the pushrod into a downward
movement to open a valve.
Adjusting spark plug gap
Plastigage
Gasket