1997 JAGUAR XJ6 fuel pump

3261 Jaguar XJ6
Safety first!0•5
Working on your car can be dangerous.
This page shows just some of the potential
risks and hazards, with the aim of creating a
safety-conscious attitude.
General hazards
Scalding
• Don’t remove the radiator or expansion
tank cap while the engine is hot.
• Engine oil, automatic transmission fluid or
power steering fluid may also be dangerously
hot if the engine has recently been running.
Burning
• Beware of burns from the exhaust system
and from any part of the engine. Brake discs
and drums can also be extremely hot
immediately after use.
Crushing
• When working under or near
a raised vehicle,
always
supplement the
jack with axle
stands, or use
drive-on
ramps.
Never
venture
under a car which
is only supported by a jack.
• Take care if loosening or tightening high-
torque nuts when the vehicle is on stands.
Initial loosening and final tightening should
be done with the wheels on the ground.
Fire
• Fuel is highly flammable; fuel vapour is
explosive.
• Don’t let fuel spill onto a hot engine.
• Do not smoke or allow naked lights
(including pilot lights) anywhere near a
vehicle being worked on. Also beware of
creating sparks
(electrically or by use of tools).
• Fuel vapour is heavier than air, so don’t
work on the fuel system with the vehicle over
an inspection pit.
• Another cause of fire is an electrical
overload or short-circuit. Take care when
repairing or modifying the vehicle wiring.
• Keep a fire extinguisher handy, of a type
suitable for use on fuel and electrical fires.
Electric shock
• Ignition HT
voltage can be
dangerous,
especially to
people with heart
problems or a
pacemaker. Don’t
work on or near the
ignition system with
the engine running or
the ignition switched on.• Mains voltage is also dangerous. Make
sure that any mains-operated equipment is
correctly earthed. Mains power points should
be protected by a residual current device
(RCD) circuit breaker.
Fume or gas intoxication
• Exhaust fumes are
poisonous; they often
contain carbon
monoxide, which is
rapidly fatal if inhaled.
Never run the
engine in a
confined space
such as a garage
with the doors shut.
• Fuel vapour is also
poisonous, as are the vapours from some
cleaning solvents and paint thinners.
Poisonous or irritant substances
• Avoid skin contact with battery acid and
with any fuel, fluid or lubricant, especially
antifreeze, brake hydraulic fluid and Diesel
fuel. Don’t syphon them by mouth. If such a
substance is swallowed or gets into the eyes,
seek medical advice.
• Prolonged contact with used engine oil can
cause skin cancer. Wear gloves or use a
barrier cream if necessary. Change out of oil-
soaked clothes and do not keep oily rags in
your pocket.
• Air conditioning refrigerant forms a
poisonous gas if exposed to a naked flame
(including a cigarette). It can also cause skin
burns on contact.
Asbestos
• Asbestos dust can cause cancer if inhaled
or swallowed. Asbestos may be found in
gaskets and in brake and clutch linings.
When dealing with such components it is
safest to assume that they contain asbestos.
Special hazards
Hydrofluoric acid
• This extremely corrosive acid is formed
when certain types of synthetic rubber, found
in some O-rings, oil seals, fuel hoses etc, are
exposed to temperatures above 400
0C. The
rubber changes into a charred or sticky
substance containing the acid. Once formed,
the acid remains dangerous for years. If it
gets onto the skin, it may be necessary to
amputate the limb concerned.
• When dealing with a vehicle which has
suffered a fire, or with components salvaged
from such a vehicle, wear protective gloves
and discard them after use.
The battery
• Batteries contain sulphuric acid, which
attacks clothing, eyes and skin. Take care
when topping-up or carrying the battery.
• The hydrogen gas given off by the battery
is highly explosive. Never cause a spark or
allow a naked light nearby. Be careful when
connecting and disconnecting battery
chargers or jump leads.
Air bags
• Air bags can cause injury if they go off
accidentally. Take care when removing the
steering wheel and/or facia. Special storage
instructions may apply.
Diesel injection equipment
• Diesel injection pumps supply fuel at very
high pressure. Take care when working on
the fuel injectors and fuel pipes.
Warning: Never expose the hands,
face or any other part of the body
to injector spray; the fuel can
penetrate the skin with potentially fatal
results.
Remember...
DO
• Do use eye protection when using power
tools, and when working under the vehicle.
• Do wear gloves or use barrier cream to
protect your hands when necessary.
• Do get someone to check periodically
that all is well when working alone on the
vehicle.
• Do keep loose clothing and long hair well
out of the way of moving mechanical parts.
• Do remove rings, wristwatch etc, before
working on the vehicle – especially the
electrical system.
• Do ensure that any lifting or jacking
equipment has a safe working load rating
adequate for the job.
A few tips
DON’T
• Don’t attempt to lift a heavy component
which may be beyond your capability – get
assistance.
• Don’t rush to finish a job, or take
unverified short cuts.
• Don’t use ill-fitting tools which may slip
and cause injury.
• Don’t leave tools or parts lying around
where someone can trip over them. Mop
up oil and fuel spills at once.
• Don’t allow children or pets to play in or
near a vehicle being worked on.

Torque wrench settings*Nm lbf ft
Camshaft bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Camshaft sprocket bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Crankshaft damper-to-crankshaft bolt
3.2 and 3.6 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 151
4.0 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 to 220 133 to 162
Crankshaft pulley to damper bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Crankshaft rear oil seal retainer bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Crankshaft sensor bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Cylinder head bolts
Step 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 44
Step 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tighten an additional 90° (1/4 turn)
Driveplate bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 to 149 91 to 110
Engine mounts
To engine block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 to 66 36 to 39
To chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 24 16 to 18
Exhaust manifold heat shield fasteners . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Exhaust manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Intake manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Oil pump bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Sump bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Sump bolts, adapter to pan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 to 54 36 to 40
Timing chain cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 to 27 16 to 20
Valve cover screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 to 12 7 to 9
*Note:Refer to Part B for additional specifications
2A•2 Engine in-car repair procedures
3261 Jaguar XJ6
1 General information
This Part of Chapter 2 is devoted to in-car
repair procedures for the in-line six-cylinder
engines. All information concerning engine
removal and refitting and engine block and
cylinder head overhaul can be found in Part B
of this Chapter.
The following repair procedures are based
on the assumption that the engine is installed
in the car. If the engine has been removed
from the car and mounted on a stand, many of
the steps outlined in this Part of Chapter 2 will
not apply. We have photographed some in-
car engine procedures with the engine on a
stand for photographic purposes.
The Specifications included in this Part of
Chapter 2 apply only to the procedures
contained in this Part. Part B of Chapter 2
includes the Specifications necessary for
cylinder head and engine block rebuilding.
2 Repair operations possible
with the engine in the car
Many repair operations can be
accomplished without removing the engine
from the car.
Clean the engine compartment and the
exterior of the engine with some type of
degreaser before any work is done. It will
make the job easier and help keep dirt out of
the internal areas of the engine.
Depending on the components involved, itmay be helpful to remove the bonnet to
improve access to the engine as repairs are
performed (refer to Chapter 11 if necessary).
Cover the wings to prevent damage to the
paint. Special pads are available, but an old
bedspread or blanket will also work.
If vacuum, exhaust, oil or coolant leaks
develop, indicating a need for gasket or seal
renewal, the repairs can generally be made
with the engine in the car. The intake and
exhaust manifold gaskets, crankshaft oil seals
and cylinder head gasket are all accessible
with the engine in place (although rear oil seal
renewal involves removal of the transmission).
The sump is difficult for a home mechanic to
replace without a hoist and other specialised
equipment, since the front suspension,
steering and crossmember must be lowered
to allow enough clearance for sump removal.
If such equipment is not available, the
alternative would be to remove the engine for
renewal of the sump or oil pump. Note:We
assume that the home mechanic does not
have access to the specialised equipment,
and have photographed our subject engine
out of the car for some procedures.
Exterior engine components, such as the
intake and exhaust manifolds, the water
pump, the starter motor, the alternator, the
distributor and the fuel system components
can be removed for repair with the engine in
place.
Since the cylinder head can be removed
with the engine in-car, camshaft and valve
component servicing can also be
accomplished. Renewal of the timing chains
and sprockets is also possible with the engine
in-car.
3 Top Dead Centre (TDC) for
number one piston- locating
1
Note:The following procedure is based on the
assumption that the distributor is correctly
installed. If you are trying to locate TDC to refit
the distributor correctly, piston position must
be determined by feeling for compression at
the number one spark plug hole, then aligning
the ignition timing marks (see paragraph 8).
1Top Dead Centre (TDC) is the highest point
in the cylinder that each piston reaches as it
travels up the cylinder bore. Each piston
reaches TDC on the compression stroke and
again on the exhaust stroke, but TDC
generally refers to piston position on the
compression stroke.
2Positioning the piston(s) at TDC is an
essential part of many procedures such as
camshaft and timing chain/sprocket removal
and distributor removal.
3Before beginning this procedure, be sure to
place the transmission in Neutral and apply
the handbrake or block the rear wheels. Also,
disable the ignition system by detaching the
coil wire from the centre terminal of the
distributor cap and grounding it on the engine
block with a jumper wire. Remove the spark
plugs (see Chapter 1).
4In order to bring any piston to TDC, the
crankshaft must be turned using one of the
methods outlined below. When looking at the
timing chain end of the engine, normal
crankshaft rotation is clockwise.
a) The preferred method is to turn the
crankshaft with a socket and ratchet

Engine block
Deck warpage limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.076 mm (0.003 inch)
Cylinder bore diameter
Standard
Size group A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90.990 to 91.003 mm (3.5823 to 3.5828 inches)
Size group B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.005 to 91.018 mm (3.5829 to 3.5834 inches)
Oversize
0.25 mm (0.010 inch) OS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.259 to 91.272 mm (3.5929 to 3.5934 inches)
0.50 mm (0.020 inch) OS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.513 to 91.526 mm (3.6029 to 3.6034 inches)
Pistons and rings
Piston-to-bore clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.017 to 0.043 mm (0.0007 to 0.0017 inch)
Piston ring end gap
No.1 (top) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.66 mm (0.016 to 0.026 inch)
No.2 (middle) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.66 mm (0.016 to 0.026 inch)
Oil ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.55 mm (0.012 to 0.022 inch)
Piston ring groove clearance
No. 1 (top) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.076 mm (0.0016 to 0.0030 inch)
No. 2 (middle) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.076 mm (0.0016 to 0.0030 inch)
Torque wrench settingsNm lbf ft
Main bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 to 142 100 to 105
Connecting rod cap nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 to 60 37 to 44
* Note:Refer to Part A for additional torque specifications.
2B•2 Engine removal and overhaul procedures
3261 Jaguar XJ6
1 General information
Included in this portion of Chapter 2 are the
general overhaul procedures for the cylinder
head and internal engine components.
The information ranges from advice
concerning preparation for an overhaul and
the purchase of replacement parts to detailed,
step-by-step procedures covering removal
and refitting of internal engine components
and the inspection of parts.
The following Sections have been written
based on the assumption that the engine has
been removed from the vehicle. For
information concerning in-vehicle engine
repair, as well as removal and refitting of the
external components necessary for the
overhaul, see Part A of this Chapter.
The Specifications included in this Part are
only those necessary for the inspection and
overhaul procedures which follow. Refer to
Part A for additional Specifications.
2 Engine overhaul-
general information
It’s not always easy to determine when, or if,
an engine should be completely overhauled,
as a number of factors must be considered.
High mileage is not necessarily an indication
that an overhaul is needed, while low mileage
doesn’t preclude the need for an overhaul.
Frequency of servicing is probably the most
important consideration. An engine that’s had
regular and frequent oil and filter changes, as
well as other required maintenance, will most
likely give many thousands of miles of reliableservice. Conversely, a neglected engine may
require an overhaul very early in its life.
Excessive oil consumption is an indication
that piston rings, valve seals and/or valve
guides are in need of attention. Make sure that
oil leaks aren’t responsible before deciding
that the rings and/or guides are bad. Perform a
cylinder compression check to determine the
extent of the work required (see Section 4).
Also check the vacuum readings under various
conditions (see Section 3).
Check the oil pressure with a gauge
installed in place of the oil pressure sender
unit (see illustrations)and compare it to this
Chapter’s Specifications. If it’s extremely low,
the bearings and/or oil pump are probably
worn out.
Loss of power, rough running, knocking or
metallic engine noises, excessive valve train
noise and high fuel consumption rates may
also point to the need for an overhaul,
especially if they’re all present at the same
time. If a complete tune-up doesn’t remedy
the situation, major mechanical work is the
only solution.An engine overhaul involves restoring the
internal parts to the specifications of a new
engine. During an overhaul, the piston rings
are replaced and the cylinder walls are
reconditioned (rebored and/or honed). If a
rebore is done by an automotive machine
workshop, new oversize pistons will also be
installed. The main bearings, big-end bearings
and camshaft bearings are generally replaced
with new ones and, if necessary, the
crankshaft may be reground to restore the
journals. Generally, the valves are serviced as
well, since they’re usually in less-than-perfect
condition at this point. While the engine is
being overhauled, other components, such as
the distributor, starter and alternator, can be
rebuilt as well. The end result should be a like
new engine that will give many trouble free
miles. Note:Critical cooling system
components such as the hoses, drivebelts,
thermostat and water pump should be
replaced with new parts when an engine is
overhauled. The radiator should be checked
carefully to ensure that it isn’t clogged or
leaking (see Chapter 3).If you purchase a
2.4a The oil pressure sender unit (arrowed)
is located in the right front corner of the
engine block, near the oil filter2.4b The oil pressure can be checked by
removing the sender unit and refitting a
pressure gauge in its place

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

working up to it in three steps. Note:Use the
old bolts for this step (save the new bolts for
final refitting).Use a thin-wall socket to avoid
erroneous torque readings that can result if
the socket is wedged between the rod cap
and nut. If the socket tends to wedge itself
between the nut and the cap, lift up on it
slightly until it no longer contacts the cap. Do
not rotate the crankshaft at any time during
this operation.
16Remove the nuts and detach the rod cap,
being careful not to disturb the Plastigauge.
17Compare the width of the crushed
Plastigauge to the scale printed on the
envelope to obtain the oil clearance (see
illustration). Compare it to this Chapter’s
Specifications to make sure the clearance is
correct.
18If the clearance is not as specified, the
bearing inserts may be the wrong size (which
means different ones will be required). Before
deciding that different inserts are needed,
make sure that no dirt or oil was between the
bearing inserts and the connecting rod or cap
when the clearance was measured. Also,
recheck the journal diameter. If the Plastigauge
was wider at one end than the other, the journal
may be tapered (refer to Section 19).
Final connecting rod refitting
19Carefully scrape all traces of the
Plastigauge material off the rod journal and/or
bearing face. Be very careful not to scratchthe bearing, use your fingernail or the edge of
a credit card to remove the Plastigauge.
20Make sure the bearing faces are perfectly
clean, then apply a uniform layer of clean
moly-base grease or engine assembly lube to
both of them. You’ll have to push the piston
higher into the cylinder to expose the face of
the bearing insert in the connecting rod, be
sure to slip the protective hoses over the
connecting rod bolts first.
21At this time, remove the original
connecting rod bolts/nuts and replace them
with new bolts/nuts. They are of a design
which requires they be used only once. The
old ones are OK for Plastigauge checking, but
for final assembly use only new connecting
rod bolts/nuts. Refit the rod cap and tighten
the nuts to the torque listed in this Chapter’s
Specifications. Again, work up to the torque in
three steps.
22Repeat the entire procedure for the
remaining pistons/connecting rod assemblies.
23The important points to remember are:
a) Keep the back sides of the bearing inserts
and the insides of the connecting rods and
caps perfectly clean during assembly..
b) Make sure you have the correct piston/
connecting rod assembly for each
cylinder.
c) The dimple on the piston must face the
front of the engine.
d) Lubricate the cylinder walls with clean oil.
e) Lubricate the bearing faces when refitting
the rod caps after the oil clearance has
been checked.
24After all the piston/connecting rod
assemblies have been properly installed,
rotate the crankshaft a number of times by
hand to check for any obvious binding.
25As a final step, the connecting rod
endplay must be checked. Refer to Section 13
for this procedure.
26Compare the measured endplay to this
Chapter’s Specifications to make sure it’s
correct. If it was correct before dismantling
and the original crankshaft and connecting
rods were reinstalled, it should still be right.
However, if new connecting rods or a new
crankshaft were installed, the endplay may beinadequate. If so, the connecting rods will
have to be removed and taken to an
automotive machine workshop for resizing.
26 Initial start-up
and running-in after overhaul
1
Warning: Have a suitable fire
extinguisher handy when starting
the engine for the first time.
1Once the engine has been installed in the
vehicle, double-check the engine oil and
coolant levels.
2With the spark plugs out of the engine and
the ignition system and fuel pump disabled,
crank the engine until oil pressure registers on
the gauge or the light goes out.
3Refit the spark plugs, hook up the plug
leads and restore the ignition system and fuel
pump functions.
4Start the engine. It may take a few
moments for the fuel system to build up
pressure, but the engine should start without
a great deal of effort.
5After the engine starts, it should be allowed
to warm up to normal operating temperature.
While the engine is warming up, make a
thorough check for fuel, oil and coolant leaks.
6Shut the engine off and recheck the engine
oil and coolant levels.
7Drive the vehicle to an area with no traffic,
accelerate from 30 to 50 mph, then allow the
vehicle to slow to 30 mph with the throttle
closed. Repeat the procedure 10 or 12 times.
This will load the piston rings and cause them
to seat properly against the cylinder walls.
Check again for oil and coolant leaks.
8Drive the vehicle gently for the first
500 miles (no sustained high speeds) and
keep a constant check on the oil level. It is not
unusual for an engine to use oil during the
running-in period.
9At approximately 500 to 600 miles, change
the oil and filter.
10For the next few hundred miles, drive the
vehicle normally. Do not pamper it or abuse it.
11After 2000 miles, change the oil and filter
again and consider the engine run-in.
2B•18 Engine removal and overhaul procedures
25.17 Measure the width of the crushed
Plastigauge to determine the big-end
bearing oil clearance
3261 Jaguar XJ6

Heating system
The heating system consists of two blower
fans, one under the dash on the right and one
on the left, and a heater core located within
the heater/air conditioning assembly which is
under the dash and behind the console.
Hoses connect the heater core to the engine
cooling system. Heater function is controlled
by the heater/air conditioning control head on
the dashboard. Hot engine coolant is
circulated through the heater core. When the
heater mode is activated, a flap door opens to
expose the heater box to the passenger
compartment. A fan switch on the control
head activates the blower motor, which forces
air through the core, heating the air.
Air conditioning system
The air conditioning system consists of a
condenser mounted in front of the radiator, an
evaporator mounted in the heat/air
conditioning assembly behind the console and
under the centre of the dash, a compressor
mounted on the engine, a filter-drier which
contains a high pressure relief valve and the
plumbing connecting all of the above.
A blower fan forces the warmer air of the
passenger compartment through the
evaporator core (sort of a radiator-in-reverse),
transferring the heat from the air to the
refrigerant. The liquid refrigerant boils off into
low pressure vapour, taking the heat with it
when it leaves the evaporator. The
compressor keeps refrigerant circulating
through the system, pumping the warmed
coolant through the condenser where it is
cooled and then circulated back to the
evaporator.
2 Antifreeze/coolant-
general information
Warning: Do not allow antifreeze
to come in contact with your
skin or painted surfaces of the
vehicle. Rinse off spills immediately withplenty of water. Antifreeze is highly toxic if
ingested. Never leave antifreeze lying
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. Many
communities have collection centres which
will see that antifreeze is disposed of
safely. Never dump used antifreeze on the
ground or into drains.
Note:Non-toxic antifreeze is now
manufactured and available at local car
accessory outlets, but even these types
should be disposed of properly.
The cooling system should be filled with a
water/ethylene-glycol based antifreeze
solution, which will prevent freezing down to
at least -20° F, or lower if local climate
requires it. It also provides protection against
corrosion and increases the coolant boiling
point.
The cooling system should be drained,
flushed and refilled every 24,000 miles or
every two years (see Chapter 1). The use of
antifreeze solutions for periods of longer than
two years is likely to cause damage and
encourage the formation of rust and scale in
the system. If your tap water is “hard”, i.e.
contains a lot of dissolved minerals, use
distilled water with the antifreeze.
Before adding antifreeze to the system,
check all hose connections, because
antifreeze tends to leak through very minute
openings. Engines do not normally consume
coolant. Therefore, if the level goes down, find
the cause and correct it.
The exact mixture of antifreeze-to-water
you should use depends on the relative
weather conditions. The mixture should
contain at least 50-percent antifreeze, but
should never contain more than 70-percent
antifreeze. Consult the mixture ratio chart on
the antifreeze container before adding
coolant. Hydrometers are available at most
car accessory outlets to test the ratio
of antifreeze to water (see illustration). Use
antifreeze which meets the vehicle
manufacturer’s specifications.
3 Thermostat-
check and renewal
2
Warning: Do not attempt to
remove the radiator cap, coolant
or thermostat until the engine
has cooled completely.
Check
1Before assuming the thermostat is
responsible for a cooling system problem,
check the coolant level (Chapter 1), drivebelt
tension (Chapter 1) and temperature gauge (or
light) operation.
2If the engine takes a long time to warm up
(as indicated by the temperature gauge or
heater operation), the thermostat is probably
stuck open. Renew the thermostat.
3If the engine runs hot, use your hand to
check the temperature of the lower radiator
hose.
Warning: Do this check with the
engine off. Do not get your
hands near the fan blades. If the
hose is not hot, but the engine
is, the thermostat is probably stuck in the
closed position, preventing the coolant
inside the engine from travelling through
the radiator. Renew the thermostat. Do not
drive the vehicle without a thermostat. The
computer may stay in open loop and
emissions and fuel economy will suffer.
4If the lower radiator hose is hot, it means
that the coolant is flowing and the thermostat
is open. Consult the Troubleshootingsection
at the front of this manual for further diagnosis.
Renewal
5Disconnect 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.
6Drain the coolant from the radiator (see
Chapter 1).
7Remove the bolts from the thermostat
cover (see illustration). If the cover doesn’t
3•2 Cooling, heating and air conditioning systems
3261 Jaguar XJ6 2.4 An inexpensive hydrometer can be
used to test the condition of your coolant
3.7 Remove the two bolts (small arrows)
holding the thermostat cover to the
housing (large arrow)

5If equipped with an automatic transmission,
disconnect the cooler lines from the radiator
(see illustrations). Disconnect the cooling fan
switch connector (see illustration 4.15).
Place a drip pan to catch the fluid and cap the
fittings. Note:The transmission oil cooler lines
enter the radiator on the left, while the power
steering cooler lines attach on the right side of
the radiator. On 1993 and 1994 models, the
cooler fittings require a spring-lock coupling
tool, normally used on fuel lines or air
conditioning lines.
6Remove the four bolts from the radiator
cowl panel and take off the panel (see
illustration).
7Lift out the radiator. Be aware of dripping
fluids and the sharp fins. Take care not to
damage the radiator fins by contact with other
parts.
8With the radiator removed, it can be
inspected for leaks, damage and internal
blockage. If repairs are necessary, have a
radiator specialist or dealer service department
perform the work, as special techniques are
required. Check the rubber mounting pads on
the bottom of the radiator (see illustration). If
they’re cracked or damaged, get new ones
before refitting the radiator.
9Bugs and dirt can be cleaned from the
radiator with compressed air and a soft brush.
Don’t bend the cooling fins as this is done.
Warning: Wear eye protection.
Refitting
10Refitting is the reverse of the removal
procedure. Be sure the rubber mounts are in
place on the bottom of the radiator.
11After refitting, fill the cooling system with
the proper mixture of antifreeze and water.
Refer to Chapter 1 if necessary.
12Start the engine and check for leaks.
Allow the engine to reach normal operating
temperature, indicated by both radiator hoses
becoming hot. Recheck the coolant level and
add more if required.
13On automatic transmission equipped
models, check and add fluid as needed and
check the power steering fluid level as well.
Expansion tank and coolant
reservoir, removal and refitting
14The expansion tank is located at the top
of the left-hand side inner wing. With the
cooling system drained below the level of the
expansion tank, remove the hoses, the
coolant level probe and the two screws
mounting it to the body (see illustration).
15Wash out and inspect the reservoir for
cracks and chafing. Renew it if damaged.16If the low-coolant level light has been
showing on the instrument panel, even when
the coolant level is correct, disconnect the
sensor’s connector and test it with an
ohmmeter (see illustration). The sensor
should be renewed if the resistance at the
connections is over 150 ohms.
Caution: Using a long-necked funnel to
add coolant can damage the sensor, which
is just below the expansion tank filler neck.
Cooling, heating and air conditioning systems 3•5
3
5.5a At the left side of the radiator,
disconnect the automatic transmission
cooler lines (small arrows) and the lower
radiator hose (larger arrow)5.5b Disconnect the power steering cooler
lines (small arrows) at the right side of the
radiator, and the upper radiator hose
(large arrow)
3261 Jaguar XJ6 5.3 Remove the clamp and the hose going
to the expansion tank
5.6 Remove the bolts (arrowed) and take
off the radiator cowl panel
5.14 The expansion tank is located on the
left inner wing
A Hose to recovery tank (where applicable)
B Hose to radiator
C Hose to thermostat housing
D Hose to water pump housing
E Mounting screws
F Low-coolant-level sensor
5.8 There are rubber mounts (arrowed)
for the radiator and the condenser -
they must be in place when these
components are reinstalled
5.16 The low-coolant-level sensor can be
tested with an ohmmeter - resistance
should be below 150 ohms - gently use a
pair of long-neck pliers to move the sensor
up and down in the tank to get a reading

3261 Jaguar XJ6
4
Chapter 4
Fuel and exhaust systems
Fuel system
Fuel pressure:kPa psi
Ignition ON, engine not running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 to 300 38 to 44
Engine idling:
Vacuum hose detached from fuel pressure regulator . . . . . . . . . . . 280 to 320 40 to 46
Vacuum hose attached to fuel pressure regulator . . . . . . . . . . . . . 210 to 260 30 to 38
Fuel system hold pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 21
Fuel injector resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 to 3.0 ohms
Idle speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Must be set by authorised service department
Torque wrench settingsNm lbf ft
Throttle body mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 14
Fuel rail mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9 Accelerator cable - removal, refitting and adjustment . . . . . . . . . . . 10
Air cleaner assembly - removal and refitting . . . . . . . . . . . . . . . . . . . 9
Catalytic converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 6
CHECK ENGINE light . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 6
Electronic Fuel Injection (EFI) system - check . . . . . . . . . . . . . . . . . . 12
Electronic Fuel Injection (EFI) system - component check
and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Electronic Fuel Injection (EFI) system - general information . . . . . . . 11
Exhaust manifold - removal and refitting . . . . . . . . . . . See Chapter 2A
Exhaust system check . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Exhaust system servicing - general information . . . . . . . . . . . . . . . . 14
Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Fuel level sender unit - check and renewal . . . . . . . . . . . . . . . . . . . . 5
Fuel lines and fittings - inspection and renewal . . . . . . . . . . . . . . . . 6
Fuel pressure relief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Fuel pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Fuel pump/fuel pressure - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Fuel system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Fuel tank - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Fuel tank cap gasket renewal . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Fuel tank cleaning and repair - general information . . . . . . . . . . . . . 8
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Intake manifold - removal and refitting . . . . . . . . . . . . See Chapter 2A
Underbonnet hose check and renewal . . . . . . . . . . . . . . See Chapter 1
4•1
Specifications 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
The fuel system consists of a fuel tank, an
electric fuel pump either located externally,
next to the fuel tank (1988 to 1990 models) or
in the fuel tank (1991 to 1994 models), an EFI
fuel pump relay and main relay, an inertia
switch, fuel injectors and fuel rail, an air
cleaner assembly and a throttle body unit.
Multi Point Fuel Injection (MPFI)
system
Multi point fuel injection uses timed
impulses to sequentially inject the fuel directly
into the intake port of each cylinder. Theinjectors are controlled by the Electronic
Control Unit (ECU). The ECU monitors various
engine parameters and delivers the exact
amount of fuel, in the correct sequence, into
the intake ports. The throttle body serves only
to control the amount of air passing into the
system. Because each cylinder is equipped
with an injector mounted immediately
adjacent to the intake valve, much better
control of the fuel/air mixture ratio is possible.
Fuel pump and lines
Fuel is circulated from the fuel tank to the
fuel injection system, and back to the fuel
tank, through a pair of metal lines running
along the underside of the vehicle. On early
models (1988 to 1990), an electric fuel pump
is attached to the chassis next to the fueltank. On later models (1991 to 1994), the fuel
pump and fuel level sender unit are located
inside the fuel tank. A vapour return system
routes all vapours and hot fuel back to the fuel
tank through a separate return line.
The fuel pump will operate as long as the
engine is cranking or running and the ECU is
receiving ignition reference pulses from the
electronic ignition system (see Chapter 5). If
there are no reference pulses, the fuel pump
will shut off after 2 or 3 seconds.Inertia switch
These models are equipped with an inertia
switch that is wired in the circuit between the
fuel pump relay, the ignition switch and the
fuel pump (refer to the wiring diagrams at the
end of Chapter 12). The inertia switch is a