1997 JAGUAR XJ6 cooling

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

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)

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

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

in the back sides of the ring grooves and the
oil hole in the lower end of each rod are clear.
6If the pistons and cylinder walls aren’t
damaged or worn excessively, and if the
engine block is not rebored, new pistons
won’t be necessary. Normal piston wear
appears as even vertical wear on the piston
thrust surfaces and slight looseness of the top
ring in its groove. New piston rings, however,
should always be used when an engine is
rebuilt.
7Carefully inspect each piston for cracks
around the skirt, at the pin bosses and at the
ring lands.
Caution: Some early 1988 3.6 litre engines
(before engine no. 9D 121113) have
incorrectly-stamped pistons. On these, the
word FRONT is actually stamped on the rear
of the pistons. Correct pistons will have the
cast arrows on the inside of the skirt to your
left when facing the word FRONT.
8Look for scoring and scuffing on the thrust
faces of the skirt, holes in the piston crown
and burned areas at the edge of the crown. If
the skirt is scored or scuffed, the engine may
have been suffering from overheating and/or
abnormal combustion, which caused
excessively high operating temperatures. The
cooling and lubrication systems should be
checked thoroughly. A hole in the piston
crown is an indication that abnormal
combustion (pre-ignition) was occurring.
Burned areas at the edge of the piston crown
are usually evidence of spark knock
(detonation). If any of the above problems
exist, the causes must be corrected or the
damage will occur again. The causes may
include intake air leaks, incorrect air/fuel
mixture, incorrect ignition timing and EGR
system malfunctions.
9Corrosion of the piston, in the form of small
pits, indicates that coolant is leaking into the
combustion chamber and/or the crankcase.
Again, the cause must be corrected or the
problem may persist in the rebuilt engine.
10Measure the piston ring groove clearance
by laying a new piston ring in each ring groove
and slipping a feeler gauge in beside it (see
illustration). Check the clearance at three or
four locations around each groove. Be sure touse the correct ring for each groove - they are
different. If the clearance is greater than that
listed in this Chapter’s Specifications, new
pistons will have to be used.
11Check the piston-to-bore clearance by
measuring the bore (see Section 16) and the
piston diameter. Make sure the pistons and
bores are correctly matched. Measure the
piston across the skirt, at a 90° angle to
the piston pin (see illustration). Subtract the
piston diameter from the bore diameter to
obtain the clearance. If it’s greater than
specified, the engine block will have to be
rebored and new pistons and rings installed.
12Check the piston-to-rod clearance by
twisting the piston and rod in opposite
directions. Any noticeable play indicates
excessive wear, which must be corrected.
13If the pistons must be removed from the
connecting rods for any reason, the rods
should be taken to an automotive machine
workshop, to be checked for bend and twist,
since automotive machine shops have special
equipment for this purpose.
14Check the connecting rods for cracks and
other damage. Temporarily remove the rod
caps, lift out the old bearing inserts, wipe the
connecting rod and cap bearing surfaces
clean and inspect them for nicks, gouges and
scratches. After checking the connecting
rods, renew the old bearings, slip the caps
into place and tighten the nuts finger tight.
Note:If the engine is being rebuilt because of
a connecting rod knock, be sure to refit new
rods.
19 Crankshaft- inspection
3
1Clean the crankshaft with solvent and dry it
with compressed air (if available). Be sure to
clean the oil holes with a stiff brush and flush
them with solvent.
2Check the main and connecting rod bearing
journals for uneven wear, scoring, pits and
cracks.
3Remove all burrs from the crankshaft oil
holes with a stone, file or scraper.4Check the remainder of the crankshaft for
cracks and other damage. It should be
magnafluxed to reveal hidden cracks - an
automotive machine workshop will handle the
procedure.
5Using a micrometer, measure the diameter
of the main and connecting rod journals and
compare the results to this Chapter’s
Specifications (see illustration). By
measuring the diameter at a number of points
around each journal’s circumference, you’ll be
able to determine whether or not the journal is
out-of-round. Take the measurement at each
end of the journal, near the crank throws, to
determine if the journal is tapered. Crankshaft
runout should be checked also, but large V-
blocks and a dial indicator are needed to do it
correctly. If you don’t have the equipment,
have a machine workshop check the runout.
6If the crankshaft journals are damaged,
tapered, out-of-round or worn beyond the
limits given in the Specifications, have the
crankshaft reground by an automotive
machine workshop. Be sure to use the correct
size bearing inserts if the crankshaft is
reconditioned.
7Check the oil seal journals at each end of
the crankshaft for wear and damage. If the
seal has worn a groove in the journal, or if it’s
nicked or scratched, the new seal may leak
when the engine is reassembled. In some
cases, an automotive machine workshop may
be able to repair the journal by pressing on a
thin sleeve. If repair isn’t feasible, a new or
different crankshaft should be installed.
8Refer to Section 20 and examine the main
and big-end bearing inserts.
20 Main and big-end bearings-
inspection and selection
3
Inspection
1Even though the main and big-end bearings
should be replaced with new ones during the
engine overhaul, the old bearings should be
retained for close examination, as they may
Engine removal and overhaul procedures 2B•13
2B
19.5 Measure the diameter of each
crankshaft journal at several points to
detect taper and out-of-round conditions
3261 Jaguar XJ6 18.10 Check the ring groove clearance
with a feeler gauge at several points
around the groove
18.11 Measure the piston diameter at a
90° angle to the piston pin, at the bottom
of the piston pin area - a precision caliper
may be used if a micrometer isn’t available

3261 Jaguar XJ6
3
Chapter 3
Cooling, heating and air conditioning systems
General
Radiator cap pressure rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.5 to 117.5 psi
Thermostat rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 to 207° F
Torque wrench settingsNm lbf ft
Coolant pipe to block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 28 16 to 21
Fan assembly-to-drive hub nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 28 16 to 21
Fan clutch-to-fan blade bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 28 16 to 21
Thermostat cover bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 28 16 to 21
Thermostat housing-to-block bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 28 16 to 21
Water pump bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 28 16 to 21 Air conditioning and heating system - check and maintenance . . . . 13
Air conditioning compressor - removal and refitting . . . . . . . . . . . . . 15
Air conditioning condenser - removal and refitting . . . . . . . . . . . . . . 16
Air conditioning evaporator and expansion valve - removal
and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Air conditioning receiver/drier - removal and refitting . . . . . . . . . . . . 14
Antifreeze/coolant - general information . . . . . . . . . . . . . . . . . . . . . . 2
Coolant level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Coolant temperature sender unit - check and renewal . . . . . . . . . . . .9
Cooling system check . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Cooling system draining, flushing and refilling . . . . . . . . See Chapter 1
Drivebelt check, adjustment and renewal . . . . . . . . . . . See Chapter 1
Engine cooling fans - check and renewal . . . . . . . . . . . . . . . . . . . . . 4Engine oil cooler - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Heater and air conditioning blower motors -circuit check
and component renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Heater and air conditioning control assembly -
check, removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Heater core - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Radiator, expansion tank and coolant reservoir -
removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Thermostat - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Underbonnet hose check and renewal . . . . . . . . . . . . . . See Chapter 1
Water pump - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Water pump and pipes - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3•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
Engine cooling system
All vehicles covered by this manual employ a
pressurised engine cooling system with
thermostatically-controlled coolant circulation.
An impeller type water pump mounted on the
front of the block pumps coolant through the
engine. The coolant flows around each cylinder
and toward the rear of the engine. Cast-in
coolant passages direct coolant around the
intake and exhaust ports, near the spark plug
areas and in proximity to the exhaust valve
guides.A wax-pellet type thermostat is located in
the thermostat housing at the front of the
engine. During warm up, the closed
thermostat prevents coolant from circulating
through the radiator. When the engine
reaches normal operating temperature, the
thermostat opens and allows hot coolant to
travel through the radiator, where it is cooled
before returning to the engine.
The cooling system is sealed by a pressure-
type radiator cap. This raises the boiling point
of the coolant, and the higher boiling point of
the coolant increases the cooling efficiency
of the radiator. If the system pressure exceeds
the cap pressure-relief value, the excess
pressure in the system forces the spring-
loaded valve inside the cap off its seat and
allows the coolant to escape through the
overflow tube into a coolant reservoir. Whenthe system cools, the excess coolant is
automatically drawn from the reservoir back
into the radiator. This type of cooling system is
known as a closed design because coolant
that escapes past the pressure cap is saved
and reused.
The Jaguar cooling system on 1988 and
1989 models has both a manifold tank and a
coolant recovery tank. The manifold tank is the
highest point in the cooling system and is the
location of the “radiator” cap (the cap is not on
the radiator). The recovery tank down in the
passenger’s footwell collects heated coolant
as described above. Models from 1990 to
1994 do not have a coolant recovery tank, but
have an enlarged manifold tank. In all models,
the recovery tank has a sensor in it to detect a
low coolant level, and the instrument panel has
a warning light to that effect.

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)

pull loose, tap it with a soft-faced hammer. Do
not use a screwdriver between the cover and
the thermostat housing.
8Remove the thermostat, noting the
direction in which it was installed in the
housing, and thoroughly clean the sealing
surfaces.
9Refit a new O-ring onto the thermostat (see
illustration). Make sure it is evenly fitted all
the way around.
10Apply a bead of RTV sealant to the
thermostat housing. Refit the thermostat and
housing, positioning the jiggle pin at the
highest point. Note:The thermostat is usually
marked TOP on the radiator side for proper
orientation.
11Tighten the cover fasteners to the torque
listed in this Chapter’s Specifications.
12Refill the cooling system, run the engine
and check for leaks and proper operation.
4 Engine cooling fans-
check and renewal
3
Mechanical fan
(1988 to 1992 models)
Warning: Keep hands, hair, tools
and clothing away from the fan
when the engine is running. Toavoid injury or damage DO NOT operate
the engine with a damaged fan. Do not
attempt to repair fan blades - renew a
damaged fan .
Check
Warning: In order to check the
fan clutch, the engine will need
to be at operating temperature,
so while going through checks
prior to Step 6 be careful that the ignition is
NOT switched on. Severe personal injury
can result!
1Symptoms of failure of the fan clutch are
continuous noisy operation, looseness,
vibration and evidence of silicone fluid leaks.
2Rock the fan back and forth by hand to
check for excessive bearing play.
3With the engine cold, turn the blades by
hand. The fan should turn freely.
4Visually inspect for substantial fluid leakage
from the fan clutch assembly, a deformed bi-
metal spring or grease leakage from the
cooling fan bearing. If any of these conditions
exist, renew the fan clutch.
5When the engine is fully warmed up, turn off
the ignition switch and disconnect the cable
from the negative battery terminal. Turn the
fan by hand. Some resistance should be felt. If
the fan turns easily, renew the fan clutch.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, makesure you have the correct activation code
before disconnecting the battery.
Removal and refitting
6Leave the battery cable disconnected (see
the Caution in Step 5).
7Remove the fan’s drivebelt (see Chapter 1).
8Remove the nuts holding the fan assembly
to the water pump (see illustration). Note:
You’ll have to “walk” the fan assembly forward
as you loosen the nuts. There is not enough
room to remove them all the way at one time.
9The fan can be removed without removing
the shroud, if you are only renewing the fan or
clutch (see illustration). Be careful not to
allow the blades contact the radiator fins.
10Remove the two fan shroud mounting
clips at the top of the shroud (see illustration).
11Lift the shroud up and out of the engine
compartment. The bottom of the fan shroud
does not have any fasteners. It has two tangs
on the bottom that slip out of slots in the body
when pulled up.
12The fan clutch can be unbolted from the
fan blade assembly for renewal (see
illustration).
Caution: To prevent silicone fluid from
draining from the clutch assembly into the
fan drive bearing and ruining the lubricant,
DON’T place the clutch in a position with
the rear pointing down. Store the clutch in
its upright position if possible.
Cooling, heating and air conditioning systems 3•3
3
4.9 The fan can be removed with the
shroud in place by angling it out of
the shroud4.10 Pry out the two clips (arrow indicates
the left one) at the top of the fan shroud
and lift out the shroud
3261 Jaguar XJ6 3.9 The thermostat is fitted with the spring end towards the
cylinder head - use a new O-ring (A) and position jiggle pin (B) up
4.8 Remove the four nuts (arrows indicate three shown here)
holding the fan/clutch assembly to the front of the water pump
4.12 Separate the fan clutch from the fan
by removing the four bolts (arrowed)