1997 JAGUAR XJ6 gas tank size

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

3261 Jaguar XJ6
MOT test checksREF•11
MExamine the handbrake mechanism,
checking for frayed or broken cables,
excessive corrosion, or wear or insecurity of
the linkage. Check that the mechanism works
on each relevant wheel, and releases fully,
without binding.
MIt is not possible to test brake efficiency
without special equipment, but a road test can
be carried out later to check that the vehicle
pulls up in a straight line.
Fuel and exhaust systems
MInspect the fuel tank (including the filler
cap), fuel pipes, hoses and unions. All
components must be secure and free from
leaks.
MExamine the exhaust system over its entire
length, checking for any damaged, broken or
missing mountings, security of the retaining
clamps and rust or corrosion.
Wheels and tyres
MExamine the sidewalls and tread area of
each tyre in turn. Check for cuts, tears, lumps,
bulges, separation of the tread, and exposure
of the ply or cord due to wear or damage.
Check that the tyre bead is correctly seated
on the wheel rim, that the valve is sound andproperly seated, and that the wheel is not
distorted or damaged.
MCheck that the tyres are of the correct size
for the vehicle, that they are of the same size
and type on each axle, and that the pressures
are correct.
MCheck the tyre tread depth. The legal
minimum at the time of writing is 1.6 mm over
at least three-quarters of the tread width.
Abnormal tread wear may indicate incorrect
front wheel alignment.
Body corrosion
MCheck the condition of the entire vehicle
structure for signs of corrosion in load-bearing
areas. (These include chassis box sections,
side sills, cross-members, pillars, and all
suspension, steering, braking system and
seat belt mountings and anchorages.) Any
corrosion which has seriously reduced the
thickness of a load-bearing area is likely to
cause the vehicle to fail. In this case
professional repairs are likely to be needed.
MDamage or corrosion which causes sharp
or otherwise dangerous edges to be exposed
will also cause the vehicle to fail.
Petrol models
MHave the engine at normal operating
temperature, and make sure that it is in good
tune (ignition system in good order, air filter
element clean, etc).
MBefore any measurements are carried out,
raise the engine speed to around 2500 rpm,
and hold it at this speed for 20 seconds. Allowthe engine speed to return to idle, and watch
for smoke emissions from the exhaust
tailpipe. If the idle speed is obviously much
too high, or if dense blue or clearly-visible
black smoke comes from the tailpipe for more
than 5 seconds, the vehicle will fail. As a rule
of thumb, blue smoke signifies oil being burnt
(engine wear) while black smoke signifies
unburnt fuel (dirty air cleaner element, or other
carburettor or fuel system fault).
MAn exhaust gas analyser capable of
measuring carbon monoxide (CO) and
hydrocarbons (HC) is now needed. If such an
instrument cannot be hired or borrowed, a
local garage may agree to perform the check
for a small fee.
CO emissions (mixture)
MAt the time of writing, the maximum CO
level at idle is 3.5% for vehicles first used after
August 1986 and 4.5% for older vehicles.
From January 1996 a much tighter limit
(around 0.5%) applies to catalyst-equipped
vehicles first used from August 1992. If the
CO level cannot be reduced far enough to
pass the test (and the fuel and ignition
systems are otherwise in good condition) then
the carburettor is badly worn, or there is some
problem in the fuel injection system or
catalytic converter (as applicable).
HC emissionsMWith the CO emissions within limits, HC
emissions must be no more than 1200 ppm
(parts per million). If the vehicle fails this test
at idle, it can be re-tested at around 2000 rpm;
if the HC level is then 1200 ppm or less, this
counts as a pass.
MExcessive HC emissions can be caused by
oil being burnt, but they are more likely to be
due to unburnt fuel.
Diesel models
MThe only emission test applicable to Diesel
engines is the measuring of exhaust smoke
density. The test involves accelerating the
engine several times to its maximum
unloaded speed.
Note: It is of the utmost importance that the
engine timing belt is in good condition before
the test is carried out.
M
Excessive smoke can be caused by a dirty
air cleaner element. Otherwise, professional
advice may be needed to find the cause.
4Checks carried out on
YOUR VEHICLE’S EXHAUST
EMISSION SYSTEM

3261 Jaguar XJ6
REF•14Fault finding
2 Fuel system
Engine surges while holding accelerator steady
m mIntake air leak (Chapter 4).
m mFuel pump faulty (Chapter 4).
m mLoose fuel injector harness connections (Chapters 4 and 6).
m mDefective ECU (Chapter 6).
Pinking or knocking engine sounds during
acceleration or uphill
m mIncorrect grade of fuel.
m mDistributor installed incorrectly (Chapter 5).
m mFuel injection system in need of adjustment (Chapter 4).
m mImproper or damaged spark plugs or wires (Chapter 1).
m mWorn or damaged distributor components (Chapter 5).
m mFaulty emission system (Chapter 6).
m mVacuum leak (Chapter 4).
m mFuel rail feed (inlet) hose has hardened, resulting in knocking noise
near dash (see Chapter 4).
Engine lacks power
m mIncorrect ignition timing (Chapter 5).
m mExcessive play in distributor shaft (Chapter 5).
m mWorn rotor, distributor cap or wires (Chapters 1 and 5).
m mFaulty or incorrectly gapped spark plugs (Chapter 1).
m mFuel injection system malfunctioning (Chapter 4).
m mFaulty coil (Chapter 5).
m mBrakes binding (Chapter 1).
m mAutomatic transmission fluid level incorrect (Chapter 1).
m mFuel filter clogged and/or impurities in the fuel system (Chapter 1).
m mEmission control system not functioning properly (Chapter 6).
m mLow or uneven cylinder compression pressures (Chapter 2).
Engine rattles at start-up
m
mFailure of upper timing chain tensioner (Chapter 2).
Engine backfires
m
mEmissions system not functioning properly (Chapter 6).
m mIgnition timing incorrect (Chapter 1).
m mFaulty secondary ignition system (cracked spark plug insulator,
faulty plug leads, distributor cap and/or rotor) (Chapters 1 and 5).
m mFuel injection system malfunctioning (Chapter 4).
m mVacuum leak at fuel injector(s), intake manifold or vacuum hoses
(Chapter 4).
Engine stalls
m mIdle speed incorrect (Chapter 1).
m mFuel filter clogged and/or water and impurities in the fuel system
(Chapter 1).
m mDistributor components damp or damaged (Chapter 5).
m mFaulty emissions system components (Chapter 6).
m mFaulty or incorrectly gapped spark plugs (Chapter 1).
m mFaulty spark plug leads (Chapter 1).
m mVacuum leak in the fuel injection system, intake manifold or
vacuum hoses (Chapter 4).
Engine runs with oil pressure light on
m mLow oil level (Chapter 1).
m mIdle rpm too low (Chapter 1).
m mShort in wiring circuit (Chapter 12).
m mFaulty oil pressure sending unit (Chapter 2).
m mWorn engine bearings and/or oil pump (Chapter 2).
Engine diesels (continues to run)
after switching off
m mIdle speed too high (Chapter 4).
m mExcessive engine operating temperature (Chapter 3).
m mIncorrect fuel octane grade.
Excessive fuel consumption
m
mDirty or clogged air filter element (Chapter 1).
m mIncorrectly set ignition timing (Chapter 5).
m mEmissions system not functioning properly (Chapter 6).
m mFuel injection internal parts worn or damaged (Chapter 4).
m mLow tyre pressure or incorrect tyre size (Chapter 1).
Fuel leakage and/or fuel odour
m
mLeak in a fuel feed or vent line (Chapter 4).
m mTank overfilled.
m mFuel injector internal parts excessively worn (Chapter 4).
3 Cooling system
Overheating
m
mInsufficient coolant in system (Chapter 1).
m mWater pump drivebelt defective or out of adjustment (Chapter 1).
m mRadiator core blocked or grille restricted (Chapter 3).
m mThermostat faulty (Chapter 3).
m mRadiator cap not maintaining proper pressure (Chapter 3).
m mIgnition timing incorrect (Chapter 5).
Overcooling
m
mFaulty thermostat (Chapter 3).
External coolant leakage
m
mDeteriorated/damaged hoses; loose clamps (Chapters 1 and 3).
m mWater pump seal defective (Chapters 1 and 3).
m mLeakage from radiator core or manifold tank (Chapter 3).
m mEngine drain or water jacket core plugs leaking (Chapter 2).
m mHoses behind water pump leaking (Chapter 3).
Internal coolant leakage
m
mLeaking cylinder head gasket (Chapter 2).
m mCracked cylinder bore or cylinder head (Chapter 2).
Coolant loss
m
mToo much coolant in system (Chapter 1).
m mCoolant boiling away because of overheating (Chapter 3).
m mInternal or external leakage (Chapter 3).
m mFaulty radiator cap (Chapter 3).
Poor coolant circulation
m
mInoperative water pump (Chapter 3).
m mRestriction in cooling system (Chapters 1 and 3).
m mWater pump drivebelt defective/out of adjustment (Chapter 1).
m mThermostat sticking (Chapter 3).
1 Engine (continued)