differential JAGUAR XJ6 1997 2.G Workshop Manual

These models are equipped with dual overhead cam in-line six-
cylinder engines. The engines feature a computer-controlled ignition
system and electronic fuel injection. Transmissions are a four-speed
automatic equipped with a lock-up torque converter. The transmission
is mounted to the back of the engine, and power is transmitted to the
fully independent rear axle through a two-piece propshaft. The
differential is bolted solidly to a frame crossmember and drives the
wheels through driveshafts equipped with inner and outer U-joints.
The front suspension is fitted with upper and lower control arms, coil
springs and shock absorbers. The rear suspension is an independent
type suspension which also have coil spring/shock absorber
assemblies and a lower control arm. The rear driveshaft acts as the
upper control arm.
Power-assisted Anti-lock Brake Systems (ABS) with four-wheel disc
brakes are standard equipment on all Jaguar XJ6 models covered in
this manual. Power rack-and-pinion steering is also standard
equipment.
Your Jaguar manual
The aim of this manual is to help you get the best value from your
vehicle. It can do so in several ways. It can help you decide what work
must be done (even should you choose to get it done by a garage). It
will also provide information on routine maintenance and servicing, and
give a logical course of action and diagnosis when random faults
occur. However, it is hoped that you will use the manual by tackling the
work yourself. On simpler jobs it may even be quicker than booking the
car into a garage and going there twice, to leave and collect it. Perhaps
most important, a lot of money can be saved by avoiding the costs a
garage must charge to cover its labour and overheads.
The manual has drawings and descriptions to show the function of
the various components so that their layout can be understood. Tasks
are described and photographed in a clear step-by-step sequence.
Notes for UK readers
Because this manual was originally written in the US, its layout
differs from our UK-originated manuals. The preliminary and reference
sections have been re-written specifically for the UK market, and the
maintenance schedule has been amended to suit UK vehicles.
However, it will be noticed that some references to componentsremain in the US style; the UK equivalent of US components and
various other US words is given in the Section headed “Use of
English”. It should be remembered that the project vehicle used in the
main Chapters of this manual was a left-hand drive US model;
therefore, the position of the steering wheel, steering column and
pedals, etc. will be on the opposite side of the vehicle on UK models.
References to “right” and “left” will need to be considered carefully to
decide which applies to UK models (eg the headlight dipped beams
should be adjusted to dip to the left of the headlight vertical line
described in Chapter 12, instead of to the right on US models). In other
instances, no reference is made to the location of a particular item, but
that item may be located on the opposite side of the vehicle on UK
models. Reference to the underbonnet photos at the start of Chapter 1
will give the reader the location of the engine compartment
components on UK models.
All specifications in the main Chapters of the manual appear in
Imperial form; the equivalent metric values can be calculated using the
“Conversion factors”page.
The only other major difference between UK and US models is in the
level of emission control equipment fitted to the vehicle. To meet the
strict emission standards present in the US, all vehicles for that market
are fitted with various emission control systems (see Chapter 6), most
of which are not fitted to the corresponding UK model, especially so on
early models. Therefore, a lot of the information contained in Chapter 6
is not applicable to UK models.
Acknowledgements
Thanks are due to Jean Preis, Rich Wilson and Ray Marcuse of
Silver Star Jaguar (Thousand Oaks, CA), Rick Calaci of Conejo Imports
(Newbury Park, CA) and Jim Strohmeier and Jonathan Lund of British
Motor Cars (Thousand Oaks, CA), for providing valuable technical
information. Technical writers who contributed to this project include
Jeff Kibler, Robert Maddox and Jay Storer.
We take great pride in the accuracy of information given in this
manual, but vehicle manufacturers make alterations and design
changes during the production run of a particular vehicle of which
they do not inform us. No liability can be accepted by the authors
or publishers for loss, damage or injury caused by any errors in, or
omissions from, the information given.
0•4Introduction
3261 Jaguar XJ6
Haynes mechanic, author and photographer with 1989 Jaguar XJ6

0•16Lubricants, fluids and tyre pressures
3261 Jaguar XJ6
Lubricants and fluids
Engine . . . . . . . . . . . . . . . . . . . . . . . . . . Multigrade engine oil to API SG or higher (Duckhams QS, QXR, Hypergrade Plus,
Hypergrade, or 10W-40 Motor Oil)
Cooling system . . . . . . . . . . . . . . . . . . . Ethylene glycol based (phosphate free) antifreeze
(Duckhams Antifreeze and Summer Coolant)
Automatic transmission . . . . . . . . . . . . Dexron type II automatic transmission fluid (ATF) (Duckhams Uni-Matic)
Differential:
Standard differential . . . . . . . . . . . . . . SAE EP90 to API GL5 (Duckhams 80W-90S Gear Oil)
Powr-lok differential . . . . . . . . . . . . . . . SAE 90 to API GL5 (Duckhams Hypoid 90 DL)
Braking system . . . . . . . . . . . . . . . . . . . Hydraulic fluid to DOT 4 (Duckhams Universal Brake and Clutch Fluid)
Power steering (with separate reservoir) .dependent on year of manufacture and system fitted - refer to your Jaguar dealer
Power hydraulic system . . . . . . . . . . . . . Castrol or Jaguar hydraulic system mineral oil (HSMO) Refer to your Jaguar dealer
Tyre pressures
Note:Tyre pressures must always be checked with the tyres cold to ensure accuracy.
Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 psi (2.3 bar)
Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 psi (2.3 bar)
Note:Jaguar state that the tyre pressures maybe reduced by up to 8 psi (0.6 bar) on the front tyres and 6 psi (0.4 bar) on the rear
tyres to increase the ride comfort. This is only allowable if the vehicle is not to be driven at speeds in excess of 100 mph (160 kmh);
if speeds are to exceed this, the tyres must be run at the specified pressures.
Oils perform vital tasks in all engines. The
higher the engine’s performance, the greater
the demand on lubricants to minimise wear as
well as optimise power and economy.
Duckhams tailors lubricants to the highest
technical standards, meeting and exceeding
the demands of all modern engines.
HOW ENGINE OIL WORKS
• Beating friction
Without oil, the surfaces inside your engine
which rub together will heat, fuse and quickly
cause engine seizure. Oil, and its special
additives, forms a molecular barrier between
moving parts, to stop wear and minimise heat
build-up.
• Cooling hot spots
Oil cools parts that the engine’s water-based
coolant cannot reach, bathing the combustion
chamber and pistons, where temperatures
may exceed 1000°C. The oil assists intransferring the heat to the engine cooling
system. Heat in the oil is also lost by air flow
over the sump, and via any auxiliary oil cooler.
• Cleaning the inner engine
Oil washes away combustion by-products
(mainly carbon) on pistons and cylinders,
transporting them to the oil filter, and holding
the smallest particles in suspension until they
are flushed out by an oil change. Duckhams
oils undergo extensive tests in the laboratory,
and on the road.
Engine oil types
Mineral oilsare the “traditional” oils,
generally suited to older engines and cars not
used in harsh conditions. Duckhams
Hypergrade Plus and Hypergradeare well
suited for use in most popular family cars.
Diesel oilssuch as Duckhams Dieselare
specially formulated for Diesel engines,
including turbocharged models and 4x4s.
Synthetic oilsare the state-of-the-art in
lubricants, offering ultimate protection, but at
a fairly high price. One such is Duckhams QS,
for use in ultra-high performance engines.
Semi-synthetic oilsoffer high performance
engine protection, but at less cost than full
synthetic oils. Duckhams QXRis an ideal choice
for hot hatches and hard-driven cars.
For help with technical
queries on lubricants,
call Duckhams Oils
on 0181 290 8207
Choosing your engine oil
Note: It is
antisocial and
illegal to dump oil
down the drain.
To find the
location of your
local oil recycling
bank, call this
number free.

3261 Jaguar XJ6
1
Chapter 1
Routine maintenance and servicing
Air cleaner element renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Automatic transmission fluid and filter renewal . . . . . . . . . . . . . . . . . 26
Automatic transmission fluid level check . . . . . . . . . . . . . . . . . . . . . 8
Battery check and general information . . . . . . . . . . . . . . . . . . . . . . . 6
Brake fluid renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Braking system - general check and adjustment . . . . . . . . . . . . . . . 11
Coolant renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Crankcase ventilation system check . . . . . . . . . . . . . . . . . . . . . . . . . 20
Differential oil level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Differential oil renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Drivebelt check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Engine oil and filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Exhaust system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Front wheel alignment check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Front wheel bearing check and adjustment . . . . . . . . . . . . . . . . . . . 22Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
General lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Handbrake shoes check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Headlight beam check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Hose and fluid leak check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Ignition system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Intensive maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Power hydraulic system fluid level check . . . . . . . . . . . . . . . . . . . . . 5
Propshaft check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Road test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Seat belt check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Spark plug check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Spark plug renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Steering and suspension check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1•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

Lubricants and fluids
Refer to “Weekly checks”
Capacities
Engine oil
Including oil filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0 litres
Cooling system
All models (approximate):
From dry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.8 litres
Drain and refill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 litres
Transmission
Automatic transmission (approximate):
From dry:
3.2 litre model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 litres
3.6 and 4.0 litre models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0 litres
Drain and refill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 litres
Differential
All models (approximate) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 litres
Cooling system
Antifreeze mixture:
50% antifreeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Protection down to -37°C (5°F)
55% antifreeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Protection down to -45°C (-22°F)
Note:Refer to antifreeze manufacturer for latest recommendations.
Ignition system
Spark plugs:
Type:
3.2 litre model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RC12YCC
3.6 and 4.0 litre models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RC9YCC
Electrode gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.9 mm
*The spark plug gap quoted is that recommended by Champion
for their specified plug listed above. If spark plugs of any other type
are to be fitted, refer to their manufacturer’s recommendations.
Engine firing order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5-3-6-2-4
Distributor rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clockwise
Ignition timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 5
Brakes
Disc brake pad friction material minimum thickness:
Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 mm
Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 mm
Handbrake shoe friction material minimum thickness . . . . . . . . . . . . . . 1.5 mm
Handbrake adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 to 5 clicks
Torque wrench settingsNm lbf ft
Automatic transmission sump pan bolts . . . . . . . . . . . . . . . . . . . . . . . . 8 6
Automatic transmission dipstick tube nut . . . . . . . . . . . . . . . . . . . . . . . 20 15
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 28 17 to 21
Wheel nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 75
1•2Servicing specifications
3261 Jaguar XJ6
Cylinder location and distributor rotation

The maintenance intervals in this manual are provided with the
assumption that you, not the dealer, will be carrying out the work.
These are the minimum maintenance intervals recommended by us for
vehicles driven daily. If you wish to keep your vehicle in peak condition
at all times, you may wish to perform some of these procedures moreoften. We encourage frequent maintenance, because it enhances the
efficiency, performance and resale value of your vehicle.
When the vehicle is new, it should be serviced by a factory-
authorised dealer service department, in order to preserve the factory
warranty.
Maintenance schedule 1•3
1
3261 Jaguar XJ6
Weekly, or every 250 miles (400 km)
m mCarry out all the operations given in “Weekly
checks”at the start of this manual.
m
mRenew the fuel filter (Section 18)
m mCheck the ignition system components (Section 19)
m mCheck the crankcase ventilation system
(Section 20)
m mCheck the condition and tension of the drivebelt(s)
(Section 21)
m mCheck the front wheel bearing adjustment and
repack with grease (Section 22)
m mCheck the propshaft fasteners are tightened to the
specified torque (Section 23)
m mCheck the front wheel alignment (Section 24)
m mCheck the headlight beam alignment (Section 25)
Every 7500 miles (12 000 km)
or 6 months, whichever comes first
In addition to the operations listed previously, carry out the following:
m mRenew the engine oil and filter (Section 3)
m mCheck the spark plugs (Section 4)
m mCheck the power hydraulics fluid level (Section 5)
m mCheck the battery (Section 6)
m mCheck all pipes and hoses for signs of damage or
leakage (Section 7)
m mCheck the automatic transmission fluid level
(Section 8)
m mCheck the differential oil level (Section 9)
m mCheck the condition of the exhaust system
(Section 10)
m mCheck the brake pads and discs for wear and
adjust the handbrake (Section 11)
m mCheck the steering and suspension components
for wear or damage and check the wheel nuts are
tightened to the correct torque (Section 12)
m mCheck the condition of the seat belts (Section 13)
m mLubricate all locks and hinges, and exposed cables
(Section 14)
m mCarry out a road test (Section 15)
Every 2 years, regardless of mileage
m
mRenew the coolant (Section 30)
Every 60 000 miles (96 000 km)
In addition to the operations listed previously, carry out the following:
m
mCheck the handbrake shoes for wear (Section 29)
Every 30 000 miles (48 000 km)
or 2 years, whichever comes first
In addition to the operations listed previously, carry out the following:
m mRenew the automatic transmission fluid and filter
(Section 26)
m mRenew the differential oil (Section 27)
m mRenew the brake fluid (Section 28)
Every 15 000 miles (24 000 km)
or 12 months, whichever comes first
In addition to the operations listed previously, carry out the following:
m mRenew the spark plugs (Section 16)
m mRenew the air cleaner element (Section 17)

Maintenance - component location 1•5
1
3261 Jaguar XJ6
Front underbody view
1 Air conditioning compressor
2 Drivebelts
3 Anti-roll bar
4 Alternator
5 Lower radiator hose
6 Lower control arm
7 Steering gear boot
8 Steering gear
9 Engine sump drain plug
10 Exhaust system
11 Outer tie-rod end
Rear underbody view (typical)
1 Rear suspension control arms
2 Differential drain plug
3 Differential filler plug
(not visible)
4 Exhaust pipe
5 Driveshaft
6 Silencers
7 Handbrake cable
8 Fuel filter

leak be found, renew the offending gasket or
oil seal by referring to the appropriate
Chapters in this manual.
2Also check the security and condition of all
the engine-related pipes and hoses. Ensure
that all cable ties or securing clips are in place
and in good condition. Clips which are broken
or missing can lead to chafing of the hoses,
pipes or wiring, which could cause more
serious problems in the future.
3Carefully check the radiator hoses and
heater hoses along their entire length. Renew
any hose which is cracked, swollen or
deteriorated. Cracks will show up better if
the hose is squeezed. Pay close attention
to the hose clips that secure the hoses to the
cooling system components. Hose clips can
pinch and puncture hoses, resulting in cooling
system leaks.
4Inspect all the cooling system components
(hoses, joint faces etc.) for leaks. A leak in the
cooling system will usually show up as white-
or rust-coloured deposits on the area
adjoining the leak. Where any problems of this
nature are found on system components,
renew the component or gasket with
reference to Chapter 3.
5From within the engine compartment,
check the security of all fuel hose attachments
and pipe unions, and inspect the fuel hoses
and vacuum hoses for kinks, chafing and
deterioration.
6Also check the condition of the power
steering fluid hoses and pipes.
8 Automatic transmission
fluid level check
1
1The level of the automatic transmission fluid
should be carefully maintained. Low fluid level
can lead to slipping or loss of drive, while
overfilling can cause foaming, loss of fluid and
transmission damage.
2The transmission fluid level should only be
checked when the transmission is at its
normal operating temperature.
Caution: If the vehicle has just been driven
for a long time at high speed or in city
traffic in hot weather, or if it has been
pulling a trailer, an accurate fluid level
reading cannot be obtained. Allow the fluid
to cool down for about 30 minutes.
3If the vehicle has not been driven, park the
vehicle on level ground, set the handbrake,
then start the engine and bring it to operating
temperature. While the engine is idling,
depress the brake pedal and move the
selector lever through all the gear ranges,
beginning and ending in Park.
4With the engine still idling, remove the
dipstick from its tube (see illustration). Check
the level of the fluid on the dipstick (see
illustration)and note its condition.
5Wipe the fluid from the dipstick with a clean
rag and reinsert it back into the filler tube until
the cap seats.6Pull the dipstick out again and note the fluid
level. If the transmission is cold, the level
should be in the COLD or COOL range on the
dipstick. If it is hot, the fluid level should be in
the HOT range. If the level is at the low side of
either range, add the specified transmission
fluid through the dipstick tube with a funnel.
7Add just enough of the recommended fluid
to fill the transmission to the proper level. It
takes about one pint to raise the level from the
low mark to the high mark when the fluid is
hot, so add the fluid a little at a time and keep
checking the level until it is correct.
8The condition of the fluid should also be
checked along with the level. If the fluid at the
end of the dipstick is black or a dark reddish
brown colour, or if it emits a burned smell, the
fluid should be changed (see Section 26). If
you are in doubt about the condition of the
fluid, purchase some new fluid and compare
the two for colour and smell.9 Differential oil level check
1
1The differential has a check/fill plug which
must be removed to check the lubricant level.
If the vehicle is raised to gain access to the
plug, be sure to support it safely on axle
stands - DO NOT crawl under the vehicle
when it’s supported only by the jack!2Remove the lubricant check/fill plug from
the differential (see illustration).Use a
3/8-inch drive ratchet and a short extension to
unscrew the plug.
3Use your little finger as a dipstick to make
sure the lubricant level is even with the
bottom of the plug hole. If not, use a syringe
or squeeze bottle to add the recommended
lubricant until it just starts to run out of the
opening.
4Refit the plug and tighten it securely.
10 Exhaust system check
1
1With the engine cold (at least three hours
after the vehicle has been driven), check the
complete exhaust system from its starting
point at the engine to the end of the tailpipe.
This should be done on a hoist where
unrestricted access is available.
2Check the pipes and connections for
evidence of leaks, severe corrosion or
damage. Make sure that all brackets and
hangers are in good condition and tight (see
illustration).
3At the same time, inspect the underside of
the body for holes, corrosion, open seams,
etc. which may allow exhaust gases to enter
the passenger compartment. Seal all body
openings with silicone or body putty.
4Rattles and other noises can often be
traced to the exhaust system, especially the
mounts and hangers. Try to move the pipes,
Every 7500 miles or 6 months 1•11
1
9.2 The differential check/fill plug is
located on the rear of the differential
housing - place your finger in the filler plug
hole to make sure the lubricant level is
even with the bottom of the hole
10.2 Check the exhaust system hangers
(arrowed) for damage and cracks
3261 Jaguar XJ6
8.4a The automatic transmission dipstick
(arrowed) is located in a tube which
extends forward from the transmission
8.4b Check the automatic transmission
fluid with the engine idling at operating
temperature and the gear selector in Park,
then add fluid to bring the level to the
upper mark

30 Coolant renewal
2
Warning: Do not allow engine
coolant (antifreeze) to come in
contact with your skin or painted
surfaces of the vehicle. Rinse off
spills immediately with plenty of water.
Antifreeze is highly toxic if ingested. Never
leave antifreeze laying around in an open
container or in puddles on the floor;
children and pets are attracted by it’s
sweet smell and may drink it. Check with
local authorities about disposing of used
antifreeze. Your local authority may have
collection centres which will see that
antifreeze is disposed of safely.1Periodically, the cooling system should be
drained, flushed and refilled to replenish the
antifreeze mixture and prevent formation of
rust and corrosion, which can impair the
performance of the cooling system and
cause engine damage. When the cooling
system is serviced, all hoses and the radiator
cap should be checked and renewed if
necessary.
Draining
2Apply the handbrake and block the wheels.
If the vehicle has just been driven, wait several
hours to allow the engine to cool down before
beginning this procedure.
3Remove the expansion tank pressure cap
(see illustration).
4Move a large container under the radiator
drain to catch the coolant. Then using a largescrewdriver, open the radiator drain plug and
direct the coolant into the container (see
illustration).
27 Differential oil renewal
2
1Drive the car for several miles to warm up
the differential lubricant, then raise the car
and support it securely on axle stands.
2Move a drain pan, rags, newspapers and
the required tools under the car.
3Remove the check/fill plug from the
differential. If necessary refer to Section 9 for
the check/fill plug location.
4With the drain pan under the differential,
use a ratchet and socket to loosen the drain
plug (see illustration). Note:A special pipe
plug socket may be required to complete this
procedure.
5Once loosened, carefully unscrew it with
your fingers until you can remove it from the
case. Since the lubricant will be hot, wear a
rubber glove to prevent burns.
6Allow all of the oil to drain into the pan, then
replace the drain plug and tighten it securely.
7Refer to Section 9 and fill the differential
with lubricant.
8Refit the fill plug and tighten it securely.
9Lower the vehicle. Check for leaks at the
drain plug after the first few miles of driving.
28 Brake fluid renewal
2
Warning: Brake fluid can harm
your eyes and damage painted
surfaces, so use extreme
caution when handling or
pouring it. Do not use brake fluid that has
been standing open or is more than oneyear old. Brake fluid absorbs moisture from
the air. Excess moisture can cause a
dangerous loss of braking effectiveness.
1At the specified time intervals, the brake
fluid should be drained and renewed. Since
the brake fluid may drip or splash when
pouring it, place plenty of rags around the
master cylinder to protect any surrounding
painted surfaces.
2Before beginning work, purchase the
specified type of brake fluid.
3Remove the cap from the master cylinder
reservoir.
4Using a hand suction pump or similar
device, withdraw the fluid from the master
cylinder reservoir.
5Add new fluid to the master cylinder until it
rises to the base of the filler neck.
6Bleed the brake system as described in
Chapter 9 at all four brakes until new and
uncontaminated fluid flows from the bleed
screw.
7Refill the master cylinder with fluid and
check the operation of the brakes. The pedal
should feel solid when depressed, with no
sponginess.
Warning: Do not drive the car if
you are in any doubt about the
braking system.
1•20Every 30 000 miles or 2 years
27.4 The differential drain plug (arrowed)
is accessible through a hole located in the
middle of the differential support brace
30.3 Push the expansion tank pressure
cap downward and rotate anti-clockwise -
never remove it when the engine is hot!
3261 Jaguar XJ6
Every 60 000 miles (96 000 km)
29 Handbrake shoes check
2
1Remove the rear discs and inspect the
handbrake shoes as described in Chapter 9. If
the shoes are worn or damaged they must be
renewed.Warning: The dust created by
the brake system may contain
asbestos, which is harmful to
your health. Never blow it out
with compressed air and don’t inhale any
of it. An approved filtering mask should be
worn when working on the brakes. Do not,
under any circumstances, use petroleum-
based solvents to clean brake parts. Usebrake system cleaner only! Try to use non-
asbestos replacement parts whenever
possible.
Every 2 years, regardless of mileage

13Allow the bellcrank to return to the idle
position and test the adjustment once again
until the correct adjustment has been attained.
11 Electronic Fuel Injection
(EFI) system-
general information
1These models are equipped with an
Electronic Fuel Injection (EFI) system. This fuel
injection system is designed by Bosch butlicensed by Lucas and is called the Lucas LH
Engine Management system. The EFI system
is composed of three basic sub systems: fuel
system, air induction system and electronic
control system (see illustration).
Fuel system
2An electric fuel pump is located on the
chassis of the rear suspension (external) (1988
to 1990) or inside the fuel tank (1991 to 1994)
The fuel pump supplies fuel under constant
pressure to the fuel rail, which distributes fuel
evenly to all injectors. From the fuel rail, fuel is
injected into the intake ports, just above the
intake valves, by fuel injectors. The amount of
fuel supplied by the injectors is precisely
controlled by an Electronic Control Unit (ECU).
A pressure regulator controls system pressure
in relation to intake manifold vacuum. A fuel
filter between the fuel pump and the fuel rail
filters fuel to protect the components of the
system.
Air induction system
3The air system consists of an air filter
housing, a Mass Air Flow (MAF) sensor
(airflow meter), Intake Air Temperature (IAT)
sensor and a throttle body. The MAF sensor is
an information gathering device for the ECU.A heated element determines the temperature
differential by measuring the current changes
which in turn measures the mass (weight and
volume) of air entering the engine. This
information helps the ECU determine the
amount of fuel to be injected by the injectors.
The throttle plate inside the throttle body is
controlled by the driver. As the throttle plate
opens, the amount of air that can pass
through the system increases, so the
potentiometer opens further and the ECU
signals the injectors to increase the amount of
fuel delivered to the intake ports. Refer to
Chapter 6 for additional information on the
fuel injection system sensors, test procedures
and renewal procedures.
Electronic control system
4The Computer Control System controls the
EFI and other systems by means of an
Electronic Control Unit (ECU), which employs
a microcomputer. The ECU receives signals
from a number of information sensors which
monitor such variables as intake air volume,
intake air temperature, coolant temperature,
engine rpm, acceleration/deceleration and
exhaust oxygen content. These signals help
the ECU determine the injection duration
necessary for the optimum air/fuel ratio. Some
Fuel and exhaust systems 4•9
4
10.11 Rotate the bellcrank until it reaches
wide open throttle and make sure the
pointer aligns with the A on the bellcrank.
Adjust if necessary
11.1 Fuel injection and emission control component locations for the 3.6 litre 1989 XJ6
3261 Jaguar XJ6 1 Fuel pressure regulator (under
fuel rail)
2 Idle Speed Control (ISC) motor
3 Fuel pressure damper4 Bellcrank
5 Throttle body (below bellcrank)
6 Intake Air Temp. (IAT) sensor
7 Supplementary air valve8 Mass Airflow (MAF) sensor
9 Throttle potentiometer (under
throttle body)
10 Fuel rail11 Fuel injector
13 Ignition amplifier (below block
valve)
14 Distributor

42Also, check the reference voltage to the
MAF sensor from the computer. Backprobe
terminal number 6 and make sure that
approximately 5 volts is present.
Renewal
43Disconnect the electrical connector from
the MAF sensor.
44Remove the air cleaner assembly (see
Chapter 4).
45Remove the four bolts and separate the
MAF sensor from the air intake duct.
46Refitting is the reverse of removal.
Intake air temperature
(IAT) sensor
General description
47The intake air temperature sensor is
located inside the air intake duct. This sensor
acts as a resistor which changes value
according to the temperature of the air entering
the engine. Low temperatures produce a high
resistance value (for example, at 68° F the
value is 2.0 to 2.6 k-ohms) while high
temperatures produce low resistance values (at
176° F the resistance is 260 to 330 ohms. The
ECU supplies around 5 volts (reference
voltage) to the air temperature sensor.
The voltage will change according to the
temperature of the incoming air. The voltage
will be high when the air temperature is cold
and low when the air temperature is warm. Any
problems with the air temperature sensor
will usually set a code 8 (1988 and 1989) or
code 16 (1990 to 1994).
Check
48To check the air temperature sensor,
disconnect the two prong electrical connector
and turn the ignition key ON but do not start
the engine.
49Measure the voltage (reference voltage),
which should be approximately 5 volts.
50If the voltage signal is not correct, havethe ECU diagnosed by a dealer service
department or other repair workshop.
51Measure the resistance across the air
temperature sensor terminals (see illustration).
The resistance should be HIGH when the air
temperature is LOW. Next, start the engine and
let it idle. Wait awhile and let the engine reach
operating temperature. Turn the ignition OFF,
disconnect the air temperature sensor and
measure the resistance across the terminals.
The resistance should be LOW when the air
temperature is HIGH. If the sensor does not
exhibit this change in resistance, renew it with a
new part.
EGR gas temperature sensor
(1991 to 1994 models)
General description
52The EGR gas temperature sensor is
mounted in the exhaust gas transfer pipe. This
sensor detects the temperature of the exhaust
moving through the EGR valve. The information
is sent to the ECU so the EGR on/off time is
regulated precisely and efficiently.
Check
53Disconnect the harness connector for the
EGR gas temperature sensor and measure
the resistance of the sensor at the various
temperatures. Refer to the Specifications
listed in this Chapter for a list of the
temperatures and the resistance values.
Removal and refitting
54Disconnect the harness connector for the
EGR gas temperature sensor and using an
open-end spanner, remove the sensor from
the EGR adapter under the intake manifold.
55Refitting is the reverse of removal.
Speed sensor
General description
56The speed sensor is mounted on thedifferential housing and monitors vehicle
speed by sensing the rotational speed of the
rear axle. A problem with this sensor or circuit
will set a code 68 and may also be the cause
of an inoperative speedometer. If the
speedometer doesn’t work, the problem lies
in the speed sensor, the instrument cluster,
the ECU or the wiring in between. For further
diagnosis, take the vehicle to a dealer service
department or other suitably-equipped and
qualified repair workshop.
Crankshaft position sensor
57The crankshaft position sensor is located
in the front timing cover near the crankshaft
pulley (see illustration). The crankshaft
position sensor relays a signal to the ECU to
indicate the exact position (angle) of the
crankshaft.
Check
58The crankshaft sensor cannot be
diagnosed without the proper tools. The
Jaguar dealer uses a diagnostic scope/
computer called the JDS. Have the crankshaft
sensor diagnosed by the dealer service
department or other qualified repair workshop.
Renewal
59To renew the sensor, disconnect the
electrical connector and remove the bolt from
the crankshaft position sensor. Refitting is the
reverse of removal.
60To renew the crankshaft sensor gear,
remove the front pulley (refer to Chapter 2A).
61Be sure there is a small gap between the
crankshaft sensor and the teeth on the gear. It
should be between 0.46 to 1.07 mm (0.018 to
0.042 inch).
62Refitting is the reverse of removal. Tighten
the crankshaft sensor bolt to the torque listed
in this Chapter’s Specifications.
Emissions and engine control systems 6•7
6
3261 Jaguar XJ6 4.51 The air intake temperature sensor resistance will DECREASE
when the temperature of the air INCREASES
4.57 Location of the crankshaft position sensor