1997 JAGUAR XJ6 warning light

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

11 Cylinder head-
removal and refitting
4
Note:The engine must be completely cool
before beginning this procedure.
Removal
1Disconnect 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.
2Drain the coolant from the engine block and
radiator (see Chapter 1).
3Drain the engine oil and remove the oil filter
(see Chapter 1).
4Remove the bonnet for easier access, if
necessary (see Chapter 11).
5Remove the intake manifold (see Section 5).
6Remove the exhaust manifolds (Section 6).
7Remove the valve cover (see Section 4).
8Refer to Section 3 and Position the engine
at TDC for cylinder number 1. Remove the
distributor (see Chapter 5).
9Remove the camshafts and sprockets (see
Section 10). Place the upper chain between
the two upper chain guides and wrap a large
rubber band around the two guides, retaining
the chain and guides.
10Remove the coolant housing from the
cylinder head (see illustration).
11Remove the cylinder head-to-front cover
bolts (see illustration).
12Using a socket and breaker bar, loosen
the cylinder head bolts in quarter-turn
increments until they can be removed by
hand. Loosen the cylinder head bolts using
the opposite of the recommended tightening
sequence (see illustration 11.23)to avoid
warping or cracking the cylinder head.
13Lift the cylinder head off the engine block.
If it’s stuck, very carefully pry up at the
transmission end, beyond the gasket surface.
Caution: Though the cylinder head is
aluminium, it is still heavy, large andawkward to handle. To avoid damaging the
body during removal, use an engine hoist
to lift the cylinder head out of the engine
compartment, or have an assistant help
you.
14With the cylinder head on a workbench,
remove all external components from the
cylinder head to allow for thorough cleaning
and inspection. See Chapter 2, Part B, for
cylinder head servicing procedures.
Refitting
15The mating surfaces of the cylinder head
and engine block must be perfectly clean
when the cylinder head is installed.
16Use a gasket scraper to remove all traces
of carbon and old gasket material, then clean
the mating surfaces with lacquer thinner or
acetone. If there’s oil on the mating surfaces
when the cylinder head is installed, the gasket
may not seal correctly and leaks could
develop. When working on the engine block,
stuff the cylinders with clean workshop rags
to keep out debris. Use a vacuum cleaner to
remove material that falls into the cylinders.
Caution: Use care when cleaning the
cylinder head gasket surface. The cylinder
head and engine block are aluminium and
can be easily damaged by using sharpscraping tools. Gasket removal solvents
are available from car accessory outlets
and may be useful for safe removal of
gasket material.
17Check the engine block and cylinder head
mating surface for nicks, deep scratches and
damage from coolant corrosion. If damage is
slight, it can be removed with a file; if it’s
excessive, machining may be the only
alternative. See Part B of this Chapter for
procedures and criteria concerning the repair
of corrosion damage.
18Use a tap of the correct size to chase the
threads in the cylinder head bolt holes, then
clean the holes with compressed air - make
sure that nothing remains in the holes.
Warning: Wear eye protection
when using compressed air!
19Remove the rear cover from the cylinder
head. Clean the gasket surface and refit the
cover with a new gasket (see illustration).
Place the side of the gasket with the sealer
bead against the cylinder head, do not use
sealant on this gasket.
20Fabricate two alignment studs from the
old head bolts. Cut off the heads, then slot the
ends with a hacksaw (see illustration). New
cylinder head bolts must be used when
refitting the head.
Engine in-car repair procedures 2A•13
2A
11.19 Remove the rear cover from the
cylinder head, clean the gasket surfaces
and refit the cover with a new gasket
(arrowed) - note that the printed-on sealer
bead is placed against the cylinder head11.20 Fabricate two alignment studs from
old cylinder head bolts and refit them in
the engine block - after the cylinder head
is installed, remove the two studs
3261 Jaguar XJ6 11.10 Disconnect the hoses and remove the bolts to separate the
coolant housing (arrowed) from the cylinder head
11.11 Remove the bolts (arrowed) securing the cylinder head
to the front cover

2Use a centre punch or paint to make
alignment marks on the driveplate and
crankshaft to ensure correct alignment during
refitting(see illustration).
3Remove the bolts that secure the driveplate
to the crankshaft. If the crankshaft turns,
wedge a screwdriver through a hole in the
driveplate to keep it from turning (see
illustration).
4Remove the driveplate from the crankshaft.
A spacer is located behind the driveplate(see
illustration). Pry it off and store it with the
driveplate.
Warning: The ring-gear teeth
may be sharp, wear gloves to
protect your hands when
handling the driveplate.
Refitting
5Clean the driveplate to remove grease and
oil. Inspect the surface for cracks. Check for
cracked and broken ring gear teeth. Note:If
there is any damage to the driveplate, replace
the driveplate with a new driveplate, a new
spacer and new bolts. Improved parts are
available as a set from the dealer.
6Clean and inspect the mating surfaces of
the driveplate and the crankshaft. If the
crankshaft rear seal is leaking, renew it before
refitting the driveplate (see Section 15).
7Position the driveplate against the
crankshaft. Be sure to align the marks made
during removal. Some models may have an
alignment dowel or staggered bolt holes to
ensure correct refitting. Before refitting the
bolts, apply thread-locking compound to the
bolt threads.
8Wedge a screwdriver in the ring gear teeth
to keep the driveplate from turning and tighten
the bolts to the torque listed in this Chapter’s
Specifications. Follow a criss-cross pattern
and work up to the final torque in three or four
steps.
9The remainder of refitting is the reverse of
the removal procedure.
15 Crankshaft rear oil seal-
renewal
4
1The transmission adapter plate and
driveplate must be removed from the car for
this procedure (see Chapter 7).
2Remove the bolts, and detach the oil seal
retainer. Remove the gasket material from the
block and the seal retainer (see illustration).
3Position the oil seal and retainer assembly
between two wood blocks on a workbench
and drive the old seal out from the backside
(see illustration).
4The new seal must be driven into the
retainer plate from the engine side. Drive thenew seal into the retainer with a wood block
or a section of pipe slightly smaller in diameter
than the outside diameter of the seal (see
illustration). The seal should be driven in only
until it is flush with the transmission side of
the retainer.
Caution: The new seal comes with a
special plastic refitting sleeve inserted in
the seal. It is designed to allow the seal to
slide over the end of the crankshaft
without displacing the seal lip. Do NOT
remove this plastic sleeve until the retainer
and seal have been installed on the engine.
5Lubricate the seal area of the crankshaft
with engine oil. Apply a bead of RTV sealant
to the sealing surface of the retainer (see
illustration).
Engine in-car repair procedures 2A•17
2A
14.2 Mark the driveplate and the
crankshaft so they can be reassembled in
the same relative position14.3 Use a screwdriver to secure the
flywheel while the bolts are removed14.4 Pry off the driveplate spacer - if a
driveplate is replaced, the spacer should
be replaced also
15.2 Remove the bolts (arrowed) and the
crankshaft rear oil seal retainer from the
back of the engine block15.3 After removing the retainer assembly
from the engine block, support it between
two wood blocks and drive out the old seal
with a drift punch and hammer
15.4 Drive the new seal into the retainer
with a wood block
3261 Jaguar XJ6
15.5 Apply RTV sealant
to the sealing surface

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

11Disconnect the throttle linkage,
transmission linkage (and dipstick tube) and
speed control cable, if equipped, from the
engine (see Chapters 4 and 7).
12Refer to Part A of this Chapter and
remove the intake and exhaust manifolds.
13Unbolt the power steering pump (see
Chapter 10). Tie the pump aside without
disconnecting the hoses. Refer to Part A for
removal of the hydraulic pump (if equipped)
from the timing chain cover.
14On air-conditioned models, unbolt the
compressor and set it aside. Do not
disconnect the refrigerant hoses. Note:Wire
the compressor out of the way with a coat
hanger, don’t let the compressor hang on the
hoses.
15Refer to Part A of this Chapter and
remove the drivebelts, water pump pulley and
crankshaft pulley.
16Attach a lifting sling to the engine.
Position a hoist and connect the sling to it.
Take up the slack until there is slight tension
on the hoist.
17With a trolley jack and piece of wood
supporting the bottom of the transmission
sump, refer to Chapter 8 and remove the
driveshaft and rear transmission mount.
Warning: Do not place any part
of your body under the
engine/transmission when it’s
supported only by a hoist or
other lifting device.
18With the hoist taking the weight of the
engine, unbolt the engine mounts (see Part A
of this Chapter).
19Recheck to be sure nothing is still
connecting the engine or transmission to the
vehicle. Disconnect and label anything still
remaining.
20Slowly lift the engine/transmission out of
the vehicle (see illustration). It may be
necessary to pry the mounts away from the
frame brackets.21Move the engine away from the vehicle
and carefully lower the hoist until the
engine/transmission can be set on the floor.
Refer to Chapter 7 and remove the
transmission and converter. Refer to Part A of
this Chapter for removal of the flywheel. With
the flywheel removed, remove the four large
bolts and the transmission adapter plate from
the engine (see illustration).
22Refer to Part A of this Chapter for removal
of the rear main seal retainer plate from the
back of the engine, then lift the engine to a
position where it can be attached to a sturdy
engine stand.
Refitting
23Check the engine/transmission mounts. If
they’re worn or damaged, renew them.
24Attach the hoist and remove the engine
from the stand. Refer to Part A of this Chapter
and renew the rear main seal and retainer
plate, then reattach the transmission adapter
plate and refer to Chapter 7 for mounting the
converter and transmission.
25Carefully lower the engine into the vehicle
with the hoist. An assistant is helpful to guide
the engine clear of accessories in the engine
compartment as the engine is lowered into
place.
26Refit the engine mount bolts and tighten
them securely. Raise the back of the
transmission with the trolley jack and reattach
the transmission mount, driveshaft and shift
linkage.
27Refit the remaining components and
fasteners in the reverse order of removal.
28Add coolant, oil, power steering and
transmission fluids as needed (see Chapter 1).
29Run the engine and check for proper
operation and leaks. Shut off the engine and
recheck the fluid levels.
7 Engine rebuilding
alternatives
The do-it-yourselfer is faced with a number
of options when performing an engine
overhaul. The decision to renew the engine
block, piston/connecting rod assemblies and
crankshaft depends on a number of factors,
with the number one consideration being the
condition of the engine block. Other
considerations are cost, access to machine
workshop facilities, parts availability, time
required to complete the project and the
extent of prior mechanical experience on the
part of the do-it-yourselfer.
Some of the rebuilding alternatives include:
Individual parts- If the inspection
procedures reveal that the engine block and
most engine components are in reusable
condition, purchasing individual parts may be
the most economical alternative. The engine
block, cylinder head, crankshaft, and
piston/connecting rod assemblies should all
be inspected carefully. Even if the engine
block shows little wear, the cylinder bores
should be surface honed.
Short block- A short block consists of an
engine block with a crankshaft and
piston/connecting rod assemblies already
installed. All new bearings are incorporated
and all clearances will be correct. The existing
camshafts, valve train components, cylinder
head and external parts can be bolted to the
short block with little or no machine workshop
work necessary.
Long block- A long block consists of a
short block plus an oil pump, sump, cylinder
head, valve cover, camshaft and valve train
components, timing sprockets and chain or
gears and timing cover. All components are
installed with new bearings, seals and gaskets
Engine removal and overhaul procedures 2B•5
2B
3261 Jaguar XJ6 6.20 Lift the engine high enough to clear the vehicle, tilting it up
at the front to clear the front crossmember, then move it away
and lower the hoist
6.21 With the engine on the floor but still supported by the hoist,
remove the four large bolts (arrowed) and pull off the
transmission adapter plate

2Using a gasket scraper, remove all traces of
gasket material from the engine block. Be very
careful not to nick or gouge the gasket sealing
surfaces.
3Remove the main bearing caps and
separate the bearing inserts from the caps
and the engine block. Tag the bearings,
indicating which cylinder they were removed
from and whether they were in the cap or the
engine block, then set them aside.
4Remove all of the threaded oil gallery plugs
from the engine block. The plugs are usually
very tight - they may have to be drilled out and
the holes retapped. Use new plugs when the
engine is reassembled.
5If the engine is extremely dirty, it should be
taken to an automotive machine workshop to
be steam cleaned or hot tanked.
6After the engine block is returned, clean all
oil holes and oil galleries one more time.
Brushes specifically designed for this purpose
are available at most car accessory outlets.
Flush the passages with warm water until the
water runs clear, dry the engine block
thoroughly and wipe all machined surfaces
with a light, rust preventive oil. If you have
access to compressed air, use it to speed the
drying process and to blow out all the oil
holes and galleries. Warning: Wear eye protection
when using compressed air!
7If the engine block isn’t extremely dirty or
sludged up, you can do an adequate cleaning
job with hot soapy water and a stiff brush.
Take plenty of time and do a thorough job.
Regardless of the cleaning method used, be
sure to clean all oil holes and galleries very
thoroughly, dry the engine block completely
and coat all machined surfaces with light oil.
8The threaded holes in the engine block
must be clean to ensure accurate torque
readings during reassembly. Run the proper
size tap into each of the holes to remove rust,
corrosion, thread sealant or sludge and
restore damaged threads (see illustration). If
possible, use compressed air to clear the
holes of debris produced by this operation.
9Refit the main bearing caps and tighten the
bolts finger tight.
10After coating the sealing surfaces of the
new core plugs with suitable sealant, refit
them in the engine block (see illustration).
Make sure they’re driven in straight and
seated properly or leakage could result.
Special tools are available for this purpose,
but a large socket, with an outside diameter
that will just slip into the core plug, a 1/2-inchdrive extension and a hammer will work just
as well.
11Apply non-hardening sealant (such as
Permatex no. 2 or Teflon pipe sealant) to the
new oil gallery plugs and thread them into the
holes in the engine block. Make sure they’re
tightened securely.
12If the engine isn’t going to be
reassembled right away, cover it with a large
plastic trash bag to keep it clean.
16 Engine block- inspection
2
1Before the engine block is inspected, it
should be cleaned as described in Section 15.
2Visually check the engine block for cracks,
rust and corrosion (see illustration 10.12).
Look for stripped threads in the threaded
holes. It’s also a good idea to have the engine
block checked for hidden cracks by an
automotive machine workshop that has the
special equipment to do this type of work,
especially if the vehicle had a history of
overheating or using coolant. If defects are
found, have the engine block repaired, if
possible, or renewed. If the top of the engine
block has been eroded by coolant leakage
and the erosion is near the cylinder bores, the
engine block must be renewed.
3Check the cylinder bores for scuffing and
scoring.
4Check the cylinders for taper and out-of-
round conditions as follows (see illustrations):
5Measure the diameter of each cylinder at
the top (just under the ridge area), centre and
bottom of the cylinder bore, parallel to the
crankshaft axis.
6Next, measure each cylinder’s diameter at
the same three locations perpendicular to the
crankshaft axis.
7The taper of each cylinder is the difference
between the bore diameter at the top of the
cylinder and the diameter at the bottom. The
out-of-round specification of the cylinder bore
Engine removal and overhaul procedures 2B•11
2B
16.4a Measure the diameter of each
cylinder at 90° to engine centreline (A), and
parallel to engine centreline (B) - out-of-
round is the difference between A and B;
taper is the difference between A and B at
the top of the cylinder and A and B at the
bottom of the cylinder16.4b The ability to “feel” when the
telescoping gauge is at the correct point
will be developed over time, so work
slowly and repeat the check until you’re
satisfied that the bore measurement is
accurate
3261 Jaguar XJ6
15.8 All bolt holes in the engine block -
particularly the main bearing cap and
cylinder head bolt holes - should be
cleaned and restored with a tap (remove
debris from holes after this is done)15.10 A large socket on an extension can
be used to drive the new core plugs into
the bores
16.4c The gauge is then measured with a
micrometer to determine the bore size

is the difference between the parallel and
perpendicular readings. Compare your results
to this Chapter’s Specifications.
8If the cylinder walls are badly scuffed or
scored, or if they’re out-of-round or tapered
beyond the limits given in this Chapter’s
Specifications, have the engine block rebored
and honed at an automotive machine
workshop. If a rebore is done, oversize
pistons and rings will be required.
9Using a precision straightedge and feeler
gauge, check the engine block deck (the
surface that mates with the cylinder head) for
distortion (see illustration 10.13). If it’s
distorted beyond the specified limit, it can be
resurfaced by an automotive machine
workshop.
10If the cylinders are in reasonably good
condition and not worn to the outside of the
limits, and if the piston-to-cylinder clearances
can be maintained properly, then they don’t
have to be rebored. Honing is all that’s
necessary (refer to Section 17).
17 Cylinder honing
3
1Prior to engine reassembly, the cylinder
bores must be honed so the new piston rings
will seat correctly and provide the best
possible combustion chamber seal. Note:If
you don’t have the tools or don’t want to
tackle the honing operation, most automotive
machine shops will do it for a reasonable fee.
2Before honing the cylinders, refit the main
bearing caps (without bearing inserts) and
tighten the bolts to the specified torque.
3Two types of cylinder hones are commonly
available - the flex hone or “bottle brush” type
and the more traditional surfacing hone with
spring-loaded stones. Both will do the job, but
for the less-experienced mechanic the “bottle
brush” hone will probably be easier to use.
You’ll also need some paraffin or honing oil,
rags and a variable-speed electric drill motor.
The drill motor should be operated at a
steady, slow speed. Proceed as follows:
a) Mount the hone in the drill motor,
compress the stones and slip it into the
first cylinder (see illustration).
Warning: Be sure to wear safety
goggles or a face shield!
b) Lubricate the cylinder with plenty of
honing oil, turn on the drill and move the
hone up-and-down in the cylinder at a
pace that will produce a fine crosshatch
pattern on the cylinder walls. Ideally, the
crosshatch lines should intersect at
approximately a 60° angle (see
illustration). Be sure to use plenty of
lubricant and don’t take off any more
material than is absolutely necessary to
produce the desired finish. Note:Piston
ring manufacturers may specify a smallercrosshatch angle than the traditional 60° -
read and follow any instructions included
with the new rings.
c) Don’t withdraw the hone from the cylinder
while it’s running. Instead, shut off the drill
and continue moving the hone up-and-
down in the cylinder until it comes to a
complete stop, then compress the stones
and withdraw the hone. If you’re using a
“bottle brush” type hone, stop the drill
motor, then turn the chuck in the normal
direction of rotation while withdrawing the
hone from the cylinder.
d) Wipe the oil out of the cylinder and repeat
the procedure for the remaining cylinders.
4After the honing job is complete, chamfer
the top edges of the cylinder bores with a
small file so the rings won’t catch when the
pistons are installed. Be very careful not to
nick the cylinder walls with the end of the file.
5The entire engine block must be washed
again very thoroughly with warm, soapy water
to remove all traces of the abrasive grit
produced during the honing operation. Note:
The bores can be considered clean when a
lint-free white cloth - dampened with clean
engine oil - used to wipe them out doesn’t
pick up any more honing residue, which will
show up as grey areas on the cloth. Be sure to
run a brush through all oil holes and galleries
and flush them with running water.
6After rinsing, dry the engine block and
apply a coat of light rust preventive oil to all
machined surfaces. Wrap the engine block in
a plastic bag to keep it clean and set it aside
until reassembly.
18 Pistons/connecting rods-
inspection
2
1Before the inspection process can be
carried out, the piston/connecting rod
assemblies must be cleaned and the original
piston rings removed from the pistons. Note:
Always use new piston rings when the engine
is reassembled.
2Using a piston ring refitting tool, carefully
remove the rings from the pistons. Be careful
not to nick or gouge the pistons in the
process.
3Scrape all traces of carbon from the top of
the piston. A hand-held wire brush or a piece
of fine emery cloth can be used once the
majority of the deposits have been scraped
away. Do not, under any circumstances, use a
wire brush mounted in a drill motor to remove
deposits from the pistons. The piston material
is soft and may be eroded away by the wire
brush.
4Use a piston ring groove-cleaning tool to
remove carbon deposits from the ring
grooves. If a tool isn’t available, a piece
broken off the old ring will do the job. Be very
careful to remove only the carbon deposits -
don’t remove any metal and do not nick or
scratch the sides of the ring grooves (see
illustrations).
5Once the deposits have been removed,
clean the piston/connecting rod assemblies
with solvent and dry them with compressed
air (if available). Make sure the oil return holes
2B•12 Engine removal and overhaul procedures
17.3a A “bottle brush” hone will produce
better results if you have never done
cylinder honing before17.3b The cylinder hone should leave a
smooth, crosshatch pattern with the lines
intersecting at approximately a 60° angle
18.4a The piston ring grooves can be
cleaned with a special tool, as shown . . .18.4b . . . or a section of a broken ring
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