1997 JAGUAR XJ6 front seat

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

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)

position, a worn or weak shock absorber is
probably the reason.
4Repeat the above check at each of the
three remaining corners of the vehicle.
Under the vehicle
5Raise the vehicle with a trolley jack and
support it securely on axle stands. See
“Jacking and towing”for proper jacking
points.
6Check the shock absorbers for evidence of
fluid leakage. Make sure that any fluid noted is
from the shocks and not from any other
source. Also check the rubber mounts at each
end for deterioration If the shock absorbers
fail any of the tests above replace the shocks
as a set.
7Check the tyres for irregular wear patterns
and proper inflation. See “Weekly checks”for
information regarding tyre wear.
8Inspect the universal joint between the
steering shaft and the steering gear housing.
Check the steering gear housing for grease
leakage. Make sure that the dust seals and
boots are not damaged and that the boot
clamps are not loose (see illustration). Check
the steering linkage for looseness or damage.
Look for loose bolts, broken or disconnected
parts and deteriorated rubber bushings on all
suspension and steering components (see
illustration). While an assistant turns the
steering wheel from side to side, check the
steering components for free movement,
chafing and binding. If the steering
components do not seem to be reacting with
the movement of the steering wheel, try to
determine where the slack is located.
9Check the balljoints moving each lower arm
up and down with a crowbar to ensure that its
balljoint has no play. If any balljoint does have
play, replace it. See Chapter 10 for the front
balljoint renewal procedure. Check the tie-rod
ends for excessive play.
10Inspect the balljoint and tie-rod end boots
for damage and leaking grease (see
illustration. Replace the balljoints and tie-rod
ends with new ones if they are damaged (see
Chapter 10).
13 Seat belt check
1
1Check the seat belts, buckles, latch plates
and guide loops for any obvious damage or
signs of wear.
2Make sure the seat belt reminder light
comes on when the key is turned on.
3The seat belts are designed to lock up
during a sudden stop or impact, yet allow free
movement during normal driving. The
retractors should hold the belt against your
chest while driving and rewind the belt when
the buckle is unlatched.
4If any of the above checks reveal problems
with the seat-belt system, replace parts as
necessary.Note:Check with your local dealer
service department; the seat belt system
should be covered under the factory warranty.
14 General lubrication
2
1Obtain a good quality, multi-purpose
lithium-base grease. You’ll also need a grease
gun and other materials to properly lubricate
the chassis (see illustration). Occasionallyplugs will be installed rather than grease
fittings. If so, grease fittings will have to be
purchased and installed.
2Look under the car and see if grease fittings
or plugs are installed. If there are plugs,
remove them and buy grease fittings, which
will thread into the component. A dealer or
motor factors will be able to supply the
correct fittings. Straight, as well as angled,
fittings are available.
3For easier access under the car, raise it with
a jack and place axle stands under the
chassis. Make sure it’s safely supported by
the stands. If the wheels are to be removed at
this interval for tyre rotation or brake
inspection, loosen the wheel nuts slightly
while the car is still on the ground.
4Before beginning, force a little grease out of
the nozzle to remove any dirt from the end of
the gun. Wipe the nozzle clean with a rag.
5With the grease gun and plenty of clean
rags, crawl under the car and begin
lubricating all the front suspension parts that
are equipped with a grease fitting.
6Lubricate the rear driveshafts (see
illustration). Wipe each fitting clean and push
the nozzle firmly over it. Pump the gun until
grease is expelled from the U-joint cap seal.
7Wipe away any excess grease from the
components and the grease fitting. Repeat
the procedure for the remaining fittings.
Every 7500 miles or 6 months 1•13
1
14.1 Materials required for chassis
and body lubrication
3261 Jaguar XJ6 12.8a Check the steering gear dust boots
for cracks and leaking steering fluid
12.8b Check the anti-roll bar bushings
(arrowed) for deterioration at the front and
the rear of the vehicle12.10 Inspect the balljoint and tie-rod end
boots for tears - tears or damage in either
boot will allow contamination of the grease
which will lead to premature failure
1 Engine oil - Light engine oil in a can like
this can be used for door and bonnet
hinges
2 Graphite spray - Used to lubricate lock
cylinders
3 Grease - Grease, in a variety of types and
weights, is available for use in a grease
gun.
4 Grease gun - A common grease gun,
shown here with a detachable hose and
nozzle, is needed for chassis lubrication.
After use, clean it thoroughly

16 Spark plug renewal
2
Refer to Section 4, renewing the plugs
regardless of their apparent condition.
17 Air cleaner element renewal
1
1The air filter is located inside a housing at
the left side of the engine compartment. To
remove the air filter, release the four spring
clips that secure the two halves of the air
cleaner housing together, then lift the cover
up and remove the air filter element (see
illustration).
Caution: Never drive the car with the air
cleaner removed. Excessive engine wear
could result and backfiring could even
cause a fire under the bonnet.
2Wipe out the inside of the air cleaner
housing.
3Place the new filter into the air cleaner
housing, making sure it seats properly.
4Refitting the cover is the reverse of removal.
18 Fuel filter renewal
2
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system.
Don’t smoke or allow open flames or bare
light bulbs near the work area, and don’t
work in a garage where a natural gas-typeappliance (such as a water heater or
clothes dryer) with a pilot light is present.
Since petrol is carcinogenic, wear latex
gloves when there’s a possibility of being
exposed to fuel, and, if you spill any fuel on
your skin, rinse it off immediately with soap
and water. Mop up any spills immediately
and do not store fuel-soaked rags where
they could ignite. The fuel system is under
constant pressure, so, if any fuel lines are
to be disconnected, the fuel pressure in
the system must be relieved first (see
Chapter 4 for more information). When you
perform any kind of work on the fuel
system, wear safety glasses and have a
Class B type fire extinguisher on hand.
1The canister type filter is mounted
underneath the car on the passenger’s side
frame rail just in front of the left rear tyre.
2Depressurise the fuel system (refer to
Chapter 4), then disconnect the cable from
the negative terminal of the battery.
3On 1988 to 1990 models, detach the banjo
bolt from the outlet side of the filter then
remove the union from the inlet side of the
filter. Unscrew the filter mounting bolt and
remove the filter (see illustration).
4On 1991 to 1994 models, the fuel filter has
quick-disconnect fittings that do not require 8Clean and lubricate the handbrake cable,
along with the cable guides and levers. This
can be done by smearing some of the chassis
grease onto the cable and its related parts
with your fingers.
9Open the bonnet and smear a little chassis
grease on the bonnet latch mechanism. Have
an assistant pull the bonnet release lever from
inside the car as you lubricate the cable at the
latch.
10Lubricate all the hinges (door, bonnet,
etc.) with engine oil to keep them in proper
working order.
11The key lock cylinders can be lubricated
with spray graphite or silicone lubricant, which
is available at motor factors.12Lubricate the door weather-stripping with
silicone spray. This will reduce chafing and
retard wear.
15 Road test
1
Instruments and electrical
equipment
1Check the operation of all instruments and
electrical equipment.
2Make sure that all instruments read
correctly, and switch on all electrical
equipment in turn, to check that it functions
properly.
Steering and suspension
3Check for any abnormalities in the steering,
suspension, handling or road “feel”.
4Drive the car, and check that there are no
unusual vibrations or noises.
5Check that the steering feels positive, with
no excessive “sloppiness”, or roughness, and
check for any suspension noises when
cornering and driving over bumps.
Drivetrain
6Check the performance of the engine and
transmission, listening for any unusual noises.7Make sure that the engine runs smoothly
when idling, and that there is no hesitation
when accelerating.
8Check that the gear changing action of the
transmission is smooth and progressive and
that the drive is taken up smoothly from a
standing start.
Braking system
9Make sure that the car does not pull to one
side when braking, and that the wheels do not
lock prematurely when braking hard.
10Check that there is no vibration through
the steering when braking.
11Check that the handbrake operates
correctly without excessive movement of the
lever, and that it holds the car stationary on a
slope.
12Test the operation of the brake servo unit
as follows. With the engine off, depress the
footbrake four or five times to exhaust the
vacuum. Hold the brake pedal depressed, then
start the engine. As the engine starts, there
should be a noticeable “give” in the brake
pedal as vacuum builds up. Allow the engine to
run for at least two minutes, and then switch it
off. If the brake pedal is depressed now, it
should be possible to detect a hiss from the
servo as the pedal is depressed. After about
four or five depressions, no further hissing
should be heard, and the pedal should feel
considerably harder.
1•14Every 7500 miles or 6 months
17.1 Detach the clips and separate the
cover, then slide the filter element out of
the housing
3261 Jaguar XJ6
14.6 Grease fittings for the rear
driveshafts are located in the centre
on each U-joint
Every 15 000 miles (24 000 km) or 12 months

and old bearings should never be installed on
new races.
15Use high-temperature front wheel bearing
grease to pack the bearings. Work the grease
completely into the bearings, forcing it
between the rollers, cone and cage from the
back side (see illustration).
16Apply a thin coat of grease to the spindle
at the outer bearing seat, inner bearing seat,
shoulder and seal seat.
17Put a small quantity of grease inboard of
each bearing race inside the hub. Using your
finger, form a dam at these points to provide
extra grease availability and to keep thinned
grease from flowing out of the bearing (see
illustration).
18Place the grease-packed inner bearing
into the rear of the hub and put a little more
grease outboard of the bearing.
19Place a new seal over the inner bearing
and tap the seal evenly into place until it’s
flush with the hub (see illustration).
20Carefully place the hub assembly onto the
spindle and push the grease-packed outer
bearing into position (see illustration).
Adjustment
21Refit the washer and spindle nut. Tighten
the nut only slightly (no more than 16Nm/12
lbf ft of torque).
22Rotate the hub slowly in a forward
direction while tightening the spindle nut toapproximately 27Nm (20 lbf ft) to seat the
bearings. Remove any grease or burrs which
could cause excessive bearing play later.
23Loosen the spindle nut 1/4-turn, then
using your hand (not a spanner of any kind),
tighten the nut until it’s snug. Refit the nut lock
and a new cotter pin through the hole in the
spindle and the slots in the nut lock. If the
nut lock slots don’t line up, remove the nut
lock and turn it slightly until they do (see
illustration).
24Bend the ends of the cotter pin until
they’re flat against the nut. Cut off any extra
length which could interfere with the dust cap.
25Refit the dust cap, tapping it into place
with a hammer.
26Refit the brake disc and caliper in the
reverse order of removal (see Chapter 9).
27Refit the wheel on the hub and tighten the
wheel nuts.
28Grasp the top and bottom of the tyre and
check the bearings in the manner described
earlier in this Section.
29Lower the vehicle and tighten the wheel
nuts to the torque listed in this Chapter’s
Specifications.
23 Propshaft check
2
1Referring to Chapter 8, check the propshaft
centre bearing, universal joint and flexible
coupling for signs of wear or damage and
check that the propshaft fixings are tightened
to the specified torque.
24 Front wheel alignment check
5
1Accurate wheel alignment requires access
to specialised test equipment and as such
should be entrusted to a suitably equipped
Jaguar dealer or a tyre specialist (refer to
Chapter 10).
25 Headlight beam check
5
1Accurate adjustment of the headlight beam
is only possible using optical beam-setting
equipment, and this work should therefore be
carried out by a Jaguar dealer or garage with
the necessary facilities (see Chapter 12).
1•18Every 15 000 miles or 12 months
22.15 Work the grease completely into the
bearing rollers22.17 Apply a thin layer of grease to the
inner and outer bearing races22.19 After refitting the inner wheel
bearing into the hub - press the grease
seal into place
22.20 Refit the hub assembly onto the
spindle - then push the grease-packed
outer bearing into position22.23 Position the nut lock on the spindle
nut so that it lines up with the cotter pin
hole - DO NOT loosen the spindle nut from
its snug position
3261 Jaguar XJ6

6Slowly and carefully press the seal and
retainer squarely onto the crankshaft (see
illustration). The plastic sleeve may be
pushed out as the retainer seats on the engine
block. Remove the plastic sleeve.
7Refit and tighten the retainer bolts to the
torque listed in this Chapter’s Specifications.
8The remaining steps are the reverse of
removal.
16 Engine mounts-
check and renewal
3
1Engine mounts seldom require attention,
but broken or deteriorated mounts should be
renewed immediately or the added strain
placed on the driveline components may
cause damage or wear.
Check
2During the check, the engine must be
raised to remove the weight from the mounts.3Raise the car and support it securely on
axle stands, then position a jack under the
engine sump. Place a large wood block
between the jack head and the sump, then
carefully raise the engine just enough to take
the weight off the mounts. Do not position the
wood block under the drain plug.
Warning: DO NOT place any part
of your body under the engine
when it’s supported by a jack!
4Check the front mounts to see if the rubber
is cracked, hardened or separated from the
metal plates. Sometimes the rubber will split
down the centre.
5Check for relative movement between the
mount plates and the engine or frame (use a
large screwdriver or pry bar to attempt to
move the mounts). If movement is noted,
lower the engine and tighten the mount
fasteners.
6Rubber preservative should be applied to
the mounts to slow deterioration.
Renewal
7Disconnect the battery negative cable.
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.
8Raise the car and support it securely on
axle stands. Support the engine as described
in paragraph 3.
Caution: Ensure the cooling fan doesn’t hit
the shroud as the engine is raised.
9To remove either engine mount, remove the
nut from the engine bracket, then raise the
engine (see illustration).
10From underneath the car, lower the
steering gear (see Chapter 10) for access to
the nut retaining the insulator to the chassis
bracket.
11Refitting is the reverse of removal. Use
thread-locking compound on the mount
bolts/nuts and be sure to tighten them
securely.
12See Chapter 7 for transmission mount
renewal.
2A•18 Engine in-car repair procedures
3261 Jaguar XJ6 15.6 Refit the retainer and oil seal onto the crankshaft
16.9 Front engine mount (A)
and retaining nut to engine bracket (B)

rebuilt engine or short block, some rebuilders
will not warranty their engines unless the
radiator has been professionally flushed. Also,
we don’t recommend overhauling the oil
pump - always refit a new one when an engine
is rebuilt.
Before beginning the engine overhaul, read
through the entire procedure to familiarise
yourself with the scope and requirements of
the job. Overhauling an engine isn’t difficult,
but it is time-consuming. Plan on the vehicle
being tied up for a minimum of two weeks,
especially if parts must be taken to an
automotive machine workshop for repair or
reconditioning. Check on availability of parts
and make sure that any necessary special
tools and equipment are obtained in advance.
Most work can be done with typical hand
tools, although a number of precision
measuring tools are required for inspecting
parts to determine if they must be renewed.
Often an automotive machine workshop will
handle the inspection of parts and offer
advice concerning reconditioning and
renewal. Note:Always wait until the engine
has been completely dismantled and all
components, especially the engine block,
have been inspected before deciding what
service and repair operations must be
performed by an automotive machine
workshop. Since the engine block’s condition
will be the major factor to consider when
determining whether to overhaul the original
engine or buy a rebuilt one, never purchase
parts or have machine work done on other
components until the engine block has been
thoroughly inspected. As a general rule, time
is the primary cost of an overhaul, so it
doesn’t pay to refit worn or substandard
parts.
If it turns out that a number of major
components are beyond reconditioning, it
may be cost effective to buy a factory-rebuilt
engine from a Jaguar dealership.
As a final note, to ensure maximum life and
minimum trouble from a rebuilt engine,
everything must be assembled with care in a
spotlessly-clean environment.
3 Vacuum gauge
diagnostic checks
2
A vacuum gauge provides valuable
information about what is going on in the
engine at a low cost. You can check for worn
rings or cylinder walls, leaking cylinder head or
intake manifold gaskets, incorrect carburettor
adjustments, restricted exhaust, stuck or
burned valves, weak valve springs, improper
ignition or valve timing and ignition problems.
Unfortunately, vacuum gauge readings are
easy to misinterpret, so they should be used
with other tests to confirm the diagnosis.
Both the absolute readings and the rate of
needle movement are important for accurate
interpretation. Most gauges measure vacuumin inches of mercury (in-Hg). As vacuum
increases (or atmospheric pressure decreases),
the reading will decrease. Also, for every
1000 foot increase in elevation above sea level;
the gauge readings will decrease about one
inch of mercury.
Connect the vacuum gauge directly to
intake manifold vacuum, not to ported (above
the throttle plate) vacuum (see illustration).
Be sure no hoses are left disconnected during
the test or false readings will result.
Before you begin the test, allow the engine
to warm up completely. Block the wheels and
set the handbrake. With the transmission in
Park, start the engine and allow it to run at
normal idle speed.
Warning: Carefully inspect the
fan blades for cracks or damage
before starting the engine. Keep
your hands and the vacuum
tester clear of the fan and do not stand in
front of the vehicle or in line with the fan
when the engine is running.
Read the vacuum gauge; an average,
healthy engine should normally produce
between 17 and 22 inches of vacuum with a
fairly steady needle.
Refer to the following vacuum gauge
readings and what they indicate about the
engines condition:
1A low steady reading usually indicates a
leaking gasket between the intake manifold
and carburettor or throttle body, a leaky
vacuum hose, late ignition timing or incorrect
camshaft timing. Check ignition timing with a
timing light and eliminate all other possible
causes, utilising the tests provided in this
Chapter before you remove the timing belt
cover to check the timing marks.
2If the reading is three to eight inches below
normal and it fluctuates at that low reading,
suspect an intake manifold gasket leak at an
intake port or a faulty injector.
3If the needle has regular drops of about two
to four inches at a steady rate the valves are
probably leaking. Perform a compression or
leak-down test to confirm this.
4An irregular drop or down-flick of the
needle can be caused by a sticking valve or
an ignition misfire. Perform a compression or
leak-down test and read the spark plugs.5A rapid vibration of about four in-Hg
vibration at idle combined with exhaust
smoke indicates worn valve guides. Perform a
leak-down test to confirm this. If the rapid
vibration occurs with an increase in engine
speed, check for a leaking intake manifold
gasket or cylinder head gasket, weak valve
springs, burned valves or ignition misfire.
6A slight fluctuation, say one inch up and
down, may mean ignition problems. Check all
the usual tune-up items and, if necessary, run
the engine on an ignition analyser.
7If there is a large fluctuation, perform a
compression or leak-down test to look for a
weak or dead cylinder or a blown cylinder
head gasket.
8If the needle moves slowly through a wide
range, check for a clogged PCV system,
incorrect idle fuel mixture, throttle body or
intake manifold gasket leaks.
9Check for a slow return after revving the
engine by quickly snapping the throttle open
until the engine reaches about 2,500 rpm and
let it shut. Normally the reading should drop to
near zero, rise above normal idle reading
(about 5 in.-Hg over) and then return to the
previous idle reading. If the vacuum returns
slowly and doesn’t peak when the throttle is
snapped shut, the rings may be worn. If there
is a long delay, look for a restricted exhaust
system (often the silencer or catalytic
converter). An easy way to check this is to
temporarily disconnect the exhaust ahead of
the suspected part and redo the test.
4 Cylinder compression check
2
1A compression check will tell you what
mechanical condition the upper end (pistons,
rings, valves, cylinder head gasket) of your
engine is in. Specifically, it can tell you if the
compression is down due to leakage caused
by worn piston rings, defective valves and
seats or a blown cylinder head gasket. Note:
The engine must be at normal operating
temperature and the battery must be fully
charged for this check.
2Begin by cleaning the area around the
spark plugs before you remove them
(compressed air should be used, if available,
otherwise a small brush or even a bicycle tyre
pump will work). The idea is to prevent dirt
from getting into the cylinders as the
compression check is being done.
3Remove all of the spark plugs from the
engine (see Chapter 1).
4Block the throttle wide open.
5Detach the coil wire from the centre of the
distributor cap and ground it on the engine
block. Use a jumper wire with alligator clips on
each end to ensure a good earth. Also,
remove the fuel pump relay (see Chapter 4) to
disable the fuel pump during the compression
test.
Engine removal and overhaul procedures 2B•3
2B
3.4 The vacuum gauge is easily attached
to a port on the intake manifold, and can
tell a lot about an engine’s state of tune
3261 Jaguar XJ6

6Refit the compression gauge in the spark
plug hole (see illustration).
7Crank the engine over at least seven
compression strokes and watch the gauge.
The compression should build up quickly in a
healthy engine. Low compression on the first
stroke, followed by gradually increasing
pressure on successive strokes, indicates
worn piston rings. A low compression reading
on the first stroke, which doesn’t build up
during successive strokes, indicates leaking
valves or a blown cylinder head gasket (a
cracked cylinder head could also be the
cause). Deposits on the undersides of the
valve heads can also cause low compression.
Record the highest gauge reading obtained.
8Repeat the procedure for the remaining
cylinders and compare the results to this
Chapter’s Specifications.
9Add some engine oil (about three squirts
from a plunger-type oil can) to each cylinder,
through the spark plug hole, and repeat the
test.
10If the compression increases after the oil
is added, the piston rings are definitely worn.
If the compression doesn’t increase
significantly, the leakage is occurring at the
valves or cylinder head gasket. Leakage past
the valves may be caused by burned valve
seats and/or faces or warped, cracked or bent
valves.
11If two adjacent cylinders have equally low
compression, there’s a strong possibility that
the cylinder head gasket between them is
blown. The appearance of coolant in the
combustion chambers or the crankcase
would verify this condition.
12If one cylinder is 20 percent lower than the
others, and the engine has a slightly rough
idle, a worn exhaust lobe on the camshaft
could be the cause.
13If the compression is unusually high, the
combustion chambers are probably coated
with carbon deposits. If that’s the case, the
cylinder head(s) should be removed and
decarbonised.
14If compression is way down or varies
greatly between cylinders, it would be a goodidea to have a leak-down test performed by
an automotive repair workshop. This test will
pinpoint exactly where the leakage is
occurring and how severe it is.
5 Engine removal-
methods and precautions
If you’ve decided that an engine must be
removed for overhaul or major repair work,
several preliminary steps should be taken.
Locating a suitable place to work is
extremely important. Adequate work space,
along with storage space for the vehicle, will
be needed. If a workshop or garage isn’t
available, at the very least a flat, level, clean
work surface made of concrete or asphalt is
required.
Cleaning the engine compartment and
engine before beginning the removal
procedure will help keep tools clean and
organised.
An engine hoist or A-frame will also be
necessary. Make sure the equipment is rated
in excess of the combined weight of the
engine and transmission. Safety is of primary
importance, considering the potential hazards
involved in lifting the engine out of the vehicle.
If the engine is being removed by a novice,
a helper should be available. Advice and aid
from someone more experienced would also
be helpful. There are many instances when
one person cannot simultaneously perform all
of the operations required when lifting the
engine out of the vehicle.
Plan the operation ahead of time. Arrange
for or obtain all of the tools and equipment
you’ll need prior to beginning the job. Some of
the equipment necessary to perform engine
removal and refitting safely and with relative
ease are (in addition to an engine hoist) a
heavy duty trolley jack, complete sets of
spanners and sockets as described in the
front of this manual, wooden blocks and
plenty of rags and cleaning solvent for
mopping up spilled oil, coolant and petrol. If
the hoist must be rented, make sure that you
arrange for it in advance and perform all of the
operations possible without it beforehand.
This will save you money and time.
Plan for the vehicle to be out of use for
quite a while. A machine workshop will be
required to perform some of the work which
the do-it-yourselfer can’t accomplish without
special equipment. These shops often have a
busy schedule, so it would be a good idea to
consult them before removing the engine in
order to accurately estimate the amount of
time required to rebuild or repair components
that may need work.
Always be extremely careful when removing
and refitting the engine. Serious injury can
result from careless actions. Plan ahead, take
your time and a job of this nature, although
major, can be accomplished successfully.
6 Engine- removal and refitting
3
Note:Read through the entire Section before
beginning this procedure. It is recommended
to remove the engine and transmission from
the top as a unit, then separate the engine
from the transmission on the workshop floor. If
the transmission is not being serviced, it is
possible to leave the transmission in the
vehicle and remove the engine from the top by
itself, by removing the crankshaft damper and
tilting up the front end of the engine for
clearance,but access to the upper
bellhousing bolts is only practical when the
rear transmission mount and driveshaft have
been removed and the transmission is angled
down with a trolley jack.
Removal
1Relieve the fuel system pressure (see
Chapter 4).
2Disconnect the battery negative cable.
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.
3Place protective covers on the wings and
cowl and remove the bonnet (see Chapter 11).
4Remove the battery and battery tray.
5Remove the air cleaner assembly (see
Chapter 4).
6Raise the vehicle and support it securely on
axle stands. Drain the cooling system and
engine oil and remove the drivebelts (see
Chapter 1).
7Clearly label, then disconnect all vacuum
lines, coolant and emissions hoses, wiring
harness connectors and earth straps.
Masking tape and/or a touch up paint
applicator work well for marking items (see
illustration). Take instant photos or sketch
the locations of components and brackets.
8Remove the cooling fan(s) and radiator (see
Chapter 3).
9Disconnect the heater hoses.
10Release the residual fuel pressure in the
tank by removing the petrol cap, then detach
the fuel lines connecting the engine to the
chassis (see Chapter 4). Plug or cap all open
fittings.
2B•4 Engine removal and overhaul procedures
4.6 A compression gauge with a threaded
fitting for the spark plug hole is preferred
over the type that requires hand pressure
to maintain the seal - be sure to block
open the throttle valve as far as possible
during the compression check!
6.7 Label both ends of each wire and hose
before disconnecting it
3261 Jaguar XJ6