1997 JAGUAR XJ6 filter

21There are variations in cooling holes in
some models. Before refitting the cylinder
head gasket, carefully check all of the
passages and bolt holes in the new cylinder
head gasket to be sure it matches your engine
block. Also make sure the new cylinder head
gasket you’re using is equipped with the
improved oil transfer hole seal (see
illustration). Position the cylinder head gasket
over the dowel pins in the engine block, make
sure TOP is facing up (see illustration).
22Carefully place the cylinder head on the
engine block without disturbing the gasket.
23Refit NEW cylinder head bolts and
following the recommended sequence,
tighten the bolts in two steps to the torque
listed in this Chapter’s Specifications(see
illustration). Step 2 of the tightening
sequence requires the bolts to be tightened
and additional 90°. An angle-torque
attachment for your torque wrench is available
at car accessory outlets. This tool provides
precision when the angle-torque method is
required and its use is highly recommended. If
the tool is not available, paint a mark on the
edge of each cylinder head bolt and tighten
the bolt until the mark is 90¡ from the startingpoint. After the cylinder head bolts are
tightened, tighten the cylinder head-to-timing-
cover bolts.
24The remaining refitting steps are the
reverse of removal. Refer to Section 10 for
replacing the camshaft sprockets and
adjusting the timing chain and tensioner. Refill
the cooling system (see Chapter 1).
25Run the engine and check for oil or
coolant leaks. Adjust the ignition timing (see
Chapter 5) and road test the car.
12 Sump- removal and refitting
4
Removal
1 Note:The sump cannot be removed with
the engine in the chassis without lowering the
front suspension and crossmember. This is a
difficult procedure for the home mechanic
without a vehicle hoist and some other
specialised tools. The other alternative
requires the engine be removed from the car
and mounted on a stand, as we haveillustrated here. Refer to Part B of this Chapter
for engine removal procedures.
2Drain the engine oil and remove the oil filter
(see Chapter 1).
3Remove the bolts and detach the sump
(see illustration).
4If it’s stuck, pry it loose very carefully with a
small screwdriver or putty knife (see
illustration). Don’t damage the mating
surfaces of the pan and engine block or oil
leaks could develop.
2A•14 Engine in-car repair procedures
3261 Jaguar XJ6 11.21a Only use a head gasket with the improved oil transfer seal
(right arrow) - the older style (left arrow) is prone to oil leaks
11.21b Place the new head gasket over the dowels in the engine
block - note the markings for UP or TOP printed on the gasket
11.23 Cylinder head bolt TIGHTENING sequence12.3 Remove the sump bolts (arrowed)
12.4 Pry at the recess in the front of the
sump to break the gasket seal - insert a
putty knife, if necessary, between the
sump and engine block

Refitting
5Remove all traces of old gasket material
and sealant from the engine block and sump.
Clean the mating surface with lacquer thinner
or acetone.
Caution: Do not use a sharp scraping tool.
Both the sump and the engine block are
aluminium and could be easily damaged.
6Make sure the threaded bolt holes in the
engine block and bellhousing are clean.
7Inspect the flange of the sump for any
cracks, pits or scratches that could cause an
oil leak.
8Remove the baffle plate at the rear of the
sump (see illustration). Clean the sump area
and the baffle, then refit the baffle.
9Inspect the oil pump pickup tube for
cracks, or foreign material blocking the screen
(see illustration).
10Apply a bead of RTV sealant to the sump
flange(see illustration). Note:The sump
must be installed within 5 minutes of sealer
application.
11Carefully position the sump on the engine
block and push it toward the transmission
adapter plate as you press it against the
engine block. Loosely refit four bolts, two on
each side of the sump. Tighten the four bolts
in a criss-cross pattern to the torque listed in
this Chapter’s Specifications, then loosen
each bolt 90°.
12Refit the two engine adapter-to-sump
bolts. Tighten the two bolts to the torque
listed in this Chapter’s Specifications, then
loosen each one 180°.
13Refit the remainder of the sump-to-engine
block bolts hand tight until all are installed,
then tighten them to the torque listed in this
Chapter’s Specifications. Lastly, tighten the
two adapter-to-sump bolts to the torque
listed in this Chapter’s Specifications.
Caution: Failure to follow this tightening
procedure could stress or possibly crack
the adapter plate.
14The remainder of refitting is the reverse of
removal. Be sure to add oil and refit a new oil
filter.
15Run the engine and check for oil pressure
and leaks.13 Oil pump- removal,
inspection and refitting
4
Removal
1Remove the sump (see Section 12).
2Unbolt the oil pickup tube and oil transfer
housing from the engine block (see
illustration). Note:Have a drain pan under the
transfer housing, as oil may drip out when the
housing is loosened from the engine block.
3Carefully pull the transfer housing and
transfer tubes to the rear to separate them
from the oil pump body.
4Bend back the locking tabs and remove thethree bolts retaining the oil pump drive
sprocket to the oil pump (see illustration).
Pull the chain and sprocket from the front of
the pump. Note:There are shims between the
sprocket and the pump. Collect them while
pulling off the sprocket.
5Remove the bolts and detach the oil pump
from the engine.
6Remove all traces of sealant and old gasket
material from the oil pump body and engine
block, then clean the mating surfaces with
lacquer thinner or acetone.
7Remove the screws and separate the front
and rear pump covers from the body. Lift out
the drive and driven rotors (see illustrations).
Note:Mark the front face of each rotor before
removing them.
Engine in-car repair procedures 2A•15
2A
12.8 Remove the bolts (arrowed) and the
sheetmetal baffle plate - clean the sump
area of the sump with the baffle removed12.9 Lubrication system components
A Oil pump
B Transfer tubesC Transfer housing
D Oil pump pickup12.10 Apply a bead of RTV sealant around
the perimeter of the sump mounting
flange, be sure to run the bead around the
outside all bolt the holes
13.7a Remove the bolts and separate the
front and rear pump covers13.7b Remove the outer rotor (A)
and inner rotor (B)
13.2 Unbolt the oil pump pickup (A) and
the bolts (B) retaining the transfer
assembly (C) to the engine block13.4 Pry back the locking tabs and remove
the three bolts retaining the oil pump drive
sprocket to the pump
3261 Jaguar XJ6

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

incorporated throughout. The refitting of
manifolds and external parts is all that’s
necessary. Engines in this rebuilt form are
available from Jaguar dealers, and some
independent rebuilders.
Give careful thought to which alternative is
best for you and discuss the situation with
local automotive machine shops, auto parts
dealers and experienced rebuilders before
ordering or purchasing replacement parts.
8 Engine overhaul-
dismantling sequence
1It’s much easier to dismantle and work on
the engine if it’s mounted on a portable
engine stand. A stand can often be rented
quite cheaply from an equipment rental yard.
Before the engine is mounted on a stand, the
driveplate and rear oil seal retainer should be
removed from the engine.
2If a stand isn’t available, it’s possible to
dismantle the engine with it blocked up on the
floor. Be extra careful not to tip or drop the
engine when working without a stand.
3If you’re going to obtain a rebuilt engine, all
external components must come off first, to
be transferred to the replacement engine, just
as they will if you’re doing a complete engine
overhaul yourself. These include:
Alternator and brackets
Emissions control components
Distributor, spark plug leads and spark
plugs
Thermostat and housing cover
Water pump
EFI components
Intake/exhaust manifolds
Oil filter
Engine mounts
Driveplate
Transmission adapter plate
Note:When removing the external
components from the engine, pay close
attention to details that may be helpful or
important during refitting. Note the installed
position of gaskets, seals, spacers, pins,
brackets, washers, bolts and other small items.
4If you’re obtaining a short block, which
consists of the engine block, crankshaft,
pistons and connecting rods all assembled,
then the cylinder head, sump and oil pump will
have to be removed as well from your engine
so that your short-block can be turned in to
the rebuilder as a core. See Engine rebuilding
alternativesfor additional information
regarding the different possibilities to be
considered.
5If you’re planning a complete overhaul, the
engine must be dismantled and the internal
components removed in the following order:
Intake and exhaust manifolds
Valve cover
Upper timing chain and camshaft
sprocketsCamshafts
Timing chain cover
Cylinder head
Sump
Oil pump
Piston/connecting rod assemblies
Crankshaft rear oil seal retainer
Crankshaft and main bearings
6Before beginning the dismantling and
overhaul procedures, make sure the following
items are available. Also, refer to Section 21
for a list of tools and materials needed for
engine reassembly.
Common hand tools
Small cardboard boxes or plastic bags for
storing parts
Gasket scraper
Ridge reamer
Micrometers
Telescoping gauges
Dial indicator set
Valve spring compressor
Cylinder surfacing hone
Piston ring groove-cleaning tool
Electric drill motor
Tap and die set
Wire brushes
Oil gallery brushes
Cleaning solvent
Special Jaguar tools
Engine lifting brackets (18G 1465)
Timing damper simulator (18E 1436)
Camshaft TDC tool (18G 1433)
9 Cylinder head- dismantling
2
Note: New and rebuilt cylinder heads are
available from Jaguar and some independent
rebuilders. Due to the fact that some
specialised tools are necessary for the
dismantling and inspection procedures, and
replacement parts may not be readily
available, it may be more practical and
economical for the home mechanic to
purchase a replacement cylinder head rather
than taking the time to dismantle, inspect and
recondition the original.1Cylinder head dismantling involves removal
of the intake and exhaust valves and related
components. It’s assumed that the lifters and
camshafts have already been removed (see
Part A as needed).
2Before the valves are removed, arrange to
label and store them, along with their related
components, so they can be kept separate
and reinstalled in the same valve guides they
are removed from (see illustration).
3Compress the springs on the first valve with
a spring compressor and remove the keepers
(see illustration). Carefully release the valve
spring compressor and remove the retainer,
the spring and the spring seat (if used). Note:
If your spring compressor does not have an
end (such as the one shown) with cut-outs on
the side, an adapter is available to use with a
standard spring compressor.
Caution: Be very careful not to nick or
otherwise damage the lifter bores when
compressing the valve springs.
4Pull the valve out of the cylinder head, then
remove the oil seal from the guide. If the valve
binds in the guide (won’t pull through), push it
back into the cylinder head and deburr the
area around the keeper groove with a fine file
or whetstone.
5Repeat the procedure for the remaining
valves. Remember to keep all the parts for
each valve together so they can be reinstalled
in the same locations.
6Once the valves and related components
have been removed and stored in an
organised manner, the cylinder head should
be thoroughly cleaned and inspected. If a
complete engine overhaul is being done,
finish the engine dismantling procedures
before beginning the cylinder head cleaning
and inspection process.
10 Cylinder head-
cleaning and inspection
2
1Thorough cleaning of the cylinder head(s)
and related valve train components, followed
by a detailed inspection, will enable you to
decide how much valve service work must be
2B•6 Engine removal and overhaul procedures
9.2 A small plastic bag, with an appropriate
label, can be used to store the valve train
components so they can be kept together
and reinstalled in the correct guide
3261 Jaguar XJ6
9.3 Compress the spring until the keepers
can be removed with a small magnetic
screwdriver or needle-nose pliers - use a
valve spring compressor with an adapter
(arrowed) to remove the keepers

reveal valuable information about the condition
of the engine (see illustration).
2Bearing failure occurs because of lack of
lubrication, the presence of dirt or other foreign
particles, overloading the engine and corrosion.
Regardless of the cause of failure, it must be
corrected before the engine is reassembled to
prevent it from happening again.
3When examining the bearings, remove
them from the engine block, the main bearing
caps, the connecting rods and the rod caps
and lay them out on a clean surface in the
same general position as their location in the
engine. This will enable you to match any
bearing problems with the corresponding
crankshaft journal.
4Dirt and other foreign particles get into the
engine in a variety of ways. It may be left in
the engine during assembly, or it may pass
through filters or the PCV system. It may get
into the oil, and from there into the bearings.
Metal chips from machining operations and
normal engine wear are often present.
Abrasives are sometimes left in engine
components after reconditioning, especially
when parts are not thoroughly cleaned using
the proper cleaning methods. Whatever the
source, these foreign objects often end up
embedded in the soft bearing material and are
easily recognised. Large particles will not
embed in the bearing and will score or gouge
the bearing and journal. The best prevention
for this cause of bearing failure is to clean all
parts thoroughly and keep everything
spotlessly clean during engine assembly.
Frequent and regular engine oil and filter
changes are also recommended.5Lack of lubrication (or lubrication
breakdown) has a number of interrelated
causes. Excessive heat (which thins the oil),
overloading (which squeezes the oil from the
bearing face) and oil leakage or throw off
(from excessive bearing clearances, worn oil
pump or high engine speeds) all contribute to
lubrication breakdown. Blocked oil passages,
which usually are the result of misaligned oil
holes in a bearing shell, will also oil starve a
bearing and destroy it. When lack of
lubrication is the cause of bearing failure, the
bearing material is wiped or extruded from the
steel backing of the bearing. Temperatures
may increase to the point where the steel
backing turns blue from overheating.
6Driving habits can have a definite effect on
bearing life. Low speed operation in too high a
gear (labouring the engine) puts extremely
high loads on bearings, which tends to
squeeze out the oil film. These loads cause
the bearings to flex, which produces fine
cracks in the bearing face (fatigue failure).
Eventually the bearing material will loosen in
pieces and tear away from the steel backing.
Short trip driving leads to corrosion of
bearings because insufficient engine heat is
produced to drive off the condensed water
and corrosive gases. These products collect
in the engine oil, forming acid and sludge. As
the oil is carried to the engine bearings, the
acid attacks and corrodes the bearing
material.
7Incorrect bearing refitting during engine
assembly will lead to bearing failure as well.
Tight-fitting bearings leave insufficient bearing
oil clearance, and this will lead to oilstarvation. Dirt or foreign particles trapped
behind a bearing insert result in high spots on
the bearing which lead to failure.
Selection
8If the original bearings are worn or
damaged, or if the oil clearances are incorrect
(see Sections 23 or 25), the following
procedures should be used to select the
correct new bearings for engine reassembly.
However, if the crankshaft has been reground,
new undersize bearings must be installed -
the following procedure should not be used if
undersize bearings are required! The
automotive machine workshop that
reconditions the crankshaft will provide or
help you select the correct-size bearings.
Regardless of how the bearing sizes are
determined, use the oil clearance, measured
with Plastigage, as a guide to ensure the
bearings are the right size.
9If you need to use a STANDARD size main
or big-end bearing, refit one that has the same
number as the original bearing. Note:4.0 litre
engines after #164637 have sized crankshafts
and bearings in three grades, indicated by
colour and letter. The codes are stamped into
the front throw of the crankshaft(see
illustration). Match replacement bearings by
the colour codes: pink (P), white (W) or
green (G) for main bearings; red (R), yellow (Y)
or blue (B) for the three grades of big-end
bearings.
10Remember, the oil clearance is the final
judge when selecting new bearing sizes. If you
have any questions or are unsure which
bearings to use, get help from a dealer parts
or service department.
2B•14 Engine removal and overhaul procedures
3261 Jaguar XJ6 20.1 When inspecting the main and big-end bearings, look for
these problems
20.9 Later model 4.0 litre engines have graded journals and
bearings, with the markings indicated on the front throw of the
crankshaft - “A” indicates the front of the engine, “B” indicates
the codes for the main journals/bearings, and “C” indicates the
connecting rod journal grades

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)

17A coolant recovery bottle is used on 1988
and 1989 models, located in the passenger’s
inner wing. The plastic inner wing splash
shield must be removed for access to the
recovery bottle (see Chapter 11). Disconnect
the recovery hose and remove the mounting
screws to renew the recovery bottle (see
illustration). Models from 1990 on do not
have the recovery bottle, but do have a larger
expansion tank.
18Refitting of either expansion tank or
recovery bottle is the reverse of removal.
6 Engine oil cooler- renewal
2
1Models from 1988 through 1991 have a
engine oil cooler, mounted ahead of the
radiator. The engine’s mechanical fan draws
air through the oil cooler, cooling off hot
engine oil that is circulated from the engine by
steel tubes. Access to the cooler is with the
grille removed (refer to Chapter 11 for grille
removal).
2To renew the oil cooler, first disconnect thetwo fittings connecting the lines to the cooler
(see illustration).
Caution: The engine should be cool for this
procedure, and you should have a small
drain pan handy because the fittings are
on the bottom of the cooler and will
probably drip some oil on dismantling.
3Remove the mounting nuts to take the
cooler out of the vehicle (see illustration).
4The other ends of the oil cooler tubes
mount to a block just below the oil filter. With
a drain pan handy, remove the nut retaining
both pipes to the block.
5Refitting the oil cooler and oil lines is the
reverse of removal. When refitting the lines to
the block or the cooler, use new O-rings.7 Water pump- check
1
1A failure in the water pump can cause
serious engine damage due to overheating.
2With the engine running and warmed to
normal operating temperature, squeeze the
upper radiator hose. If the water pump is
working properly, a pressure surge should be
felt as the hose is released.
Warning: Keep hands away from
fan blades!
3Water pumps are equipped with weep or
vent holes (see illustration). If a failure occurs
in the pump seal, coolant will leak from this
hole. In most cases it will be necessary to use
a flashlight to find the hole on the water pump
by looking through the space behind the
pulley just below the water pump shaft.
4If the water pump shaft bearings fail there
may be a howling sound at the front of the
engine while it is running. Bearing wear can be
felt if the water pump pulley is rocked up anddown. Do not mistake drivebelt slippage,
which causes a squealing sound, for water
pump failure. Spray automotive drivebelt
dressing on the belts to eliminate the belt as a
possible cause of the noise.
8 Water pump and pipes-
renewal
3
Warning: Do not start this
procedure until the engine is
completely cool.
1Disconnect the negative battery cable and
drain the cooling system (see Chapter 1).
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.
2Refer to Section 4 to remove the
mechanical fan and clutch (if applicable to
your model).
3Refer to Chapter 1 for removal of the
drivebelts.
3•6 Cooling, heating and air conditioning systems
6.3 Remove the mounting nuts (arrowed)
to take the oil cooler out
7.3 Check the weep hole (arrowed) for
signs of leakage (pump removed for
clarity) - grey discolouration is normal,
large brown stains indicates seal failure
3261 Jaguar XJ6 5.17 The recovery bottle (arrowed) on 1988 and 1989 models is
located in the footwell - disconnect the hoses and the two
mounting screws
6.2 Disconnect the two metal oil lines (arrowed) where they
mount to the bottom of the cooler - use two spanners