Jaguar X-Type Sedan and Estate (Wagon). Service manual — part 123

and repeat the compression measurement.

If the reading greatly improves then the piston rings are damaged.

If the reading stays the same then the cause is either damaged valve seats or valve stem seals.

If the measurements for two cylinders next to each other are both too low then it is very likely that the cylinder head gasket between them
is burnt through. This can also be recognized by traces of engine oil in the coolant and/or coolant in the engine oil.

Excessive Engine Oil Consumption

The amount of oil an engine uses will vary with the way the vehicle is driven in addition to normal engine-to-engine variation. This is
especially true during the first 16,100 km (10,000 miles) when a new engine is being broken in or until certain internal components become
conditioned. Vehicles used in heavy-duty operation may use more oil. The following are examples of heavy-duty operation:

Trailer towing applications.
Severe loading applications.
Sustained high speed operation.

Engines need oil to lubricate the following internal components:

Cylinder block cylinder walls.
Pistons and piston rings.
Intake and exhaust valve stems.
Intake and exhaust valve guides.
All internal engine components.

When the pistons move downward, a thin film of oil is left on the cylinder walls. As the vehicle is operated, some oil is also drawn into the
combustion chambers past the intake and exhaust valve stem seals and burned.

The following is a partial list of conditions that can affect oil consumption rates:

Engine size.
Operator driving habits.
Ambient temperatures.
Quality and viscosity of oil.

Operation under varying conditions can frequently be misleading. A vehicle that has been run for several thousand miles on short trips or in
below-freezing ambient temperatures may have consumed a "normal" amount of oil. However, when checking the engine oil level, it may
measure up to the full mark on the oil level indicator due to dilution (condensation and fuel) in the engine crankcase. The vehicle then
might be driven at high speeds on the highway where the condensation and fuel boil off. The next time the engine oil is checked it may
appear that a liter of oil was used in about 160 km (100 miles) per liter oil consumption rate is about 2,400 km (1,500 miles) per liter.

Make sure the selected engine oil meets Jaguar specification and the recommended API performance category "SG" and SAE viscosity grade
as shown in the vehicle Owner's Guide. It is also important that the engine oil is changed at the intervals specified for the typical operating
conditions.

Oil Consumption Test

The following diagnostic procedure is used to determine the source of excessive oil consumption.

• NOTE: Oil use is normally greater during the first 16,100 km (10,000 miles) of service. As mileage increases, oil use decreases. Vehicles in
normal service should get a least 16,000 km (10,000 miles) per liter. High speed driving, towing, high ambient temperature and other
factors may result in greater oil use.

1. Define excessive consumption, such as the number of miles driven per liter of oil used. Also determine customers's driving habits,

such as sustained high speed operation, towing, extended idle and other considerations.

1.

2. Verify that the engine has no external oil leaks as described under Engine Oil Leaks.

2.

3. Verify that the engine has the correct oil level.

3.

4. Verify that the engine is not being run in an overfilled condition. Check the oil level at least five minutes after a hot shutdown

with the vehicle parked on a level surface. In no case should the level be above the top of the cross-hatched area and the letter
"F" in FULL. If significantly overfilled, carry out step 5, sub steps 1 through 4.

4.

5. Carry out an oil consumption test:

1. Drain engine oil and fill with one liter less than the recommended amount.
2. Run the engine for three minutes (10 minutes if cold), and allow oil to drain back for at least five minutes with vehicle

parked on level surface.

3. Remove the oil level indicator and wipe clean. (Do not wipe with anything contaminated with silicone compounds.)

Install the oil level indicator making sure to seat the oil level indicator firmly in the oil level indicator tube. Remove the
oil level indicator and draw a mark on the back (unmarked) surface at the indicated oil level. (This level should be about
the same as the ADD mark on the face of the oil level indicator.)

4. Add one liter of oil. Start the engine and allow to idle for at least two minutes. Shut off the engine and allow the engine

oil to drain back for at least five minutes. Mark the oil level dipstick, using the procedure above. (This level may range
from slightly below the top of the cross-hatched area to slightly below the letter "F" in FULL.

5. Record the vehicles mileage.
6. Instruct the customer to drive the vehicle as usual and:

1. Check the oil level regularly at intervals of 160-240 km (100-150 miles).

2. Return to the service point when the oil level drops below the lower (ADD) mark on the oil level indicator.

3. Add only full liters of the same oil in an emergency. Note the mileage at which the oil is added.

7. Check the oil level under the same conditions and at the same location as in steps 3 and 4.

1. Measure the distance from the oil level to the UPPER mark on the oil level indicator and record.

2. Measure the distance between the two scribe marks and record.

3. Divide the first measurement by the second.

4. Divide the distance driven during the oil test by the result. This quantity is the approximate oil consumption rate in kilometers per

liter or in mile per quart.

5.

5. If the oil consumption rate is unacceptable go to Step 6.

6. Check the positive crankcase ventilation (PCV) system. Make sure the system is not plugged.

6.

7. Check for plugged oil drain-back holes in the cylinder head and cylinder block.

7.

8. If the condition still exists after carrying out the above tests go to step 9.

8.

9. Carry out a cylinder compression test. Refer to the procedure in this section : Compression Test. This can help determine the

source of oil consumption such as valves, piston rings or other areas.

9.

10. Check valve guides for excessive guide clearance. Install new valve stem seals after verifying valve guide clearance.

10.

11. Worn or damaged internal engine components can cause excessive oil consumption. Small deposits of oil on the tips of the spark

plugs can be a clue to internal oil consumption.

11.

Intake Manifold Vacuum Test

Bring the engine to normal operating temperature. Connect a vacuum gauge or equivalent to the intake manifold. Run the engine at the
specified idle speed.

The vacuum gauge should read between 51-74 kPa (15-22 in-Hg) depending upon the engine condition and the altitude at which the test is
performed. Subtract 4.0193 kPa (1 in-Hg) from the specified reading for every 304.8 m (1,000 feet) of elevation above sea level.

The reading should be steady. As necessary, adjust the gauge damper control (where used) if the needle is fluttering rapidly. Adjust the
damper until the needle moves easily without excessive flutter.

Interpreting Vacuum Gauge Readings

A careful study of the vacuum gauge reading while the engine is idling will help pinpoint trouble areas. Always conduct other appropriate
tests before arriving at a final diagnostic decision. Vacuum gauge readings, although helpful, must be interpreted carefully.

Most vacuum gauges have a normal band indicated on the gauge face.

The following are potential gauge readings. Some are normal; others should be investigated further.

1. NORMAL READING: Needle between 51-74 kPa (15-22 in-Hg) and holding steady.

1.

2. NORMAL READING DURING RAPID ACCELERATION : When the engine is rapidly accelerated (dotted needle), the needle will drop

to a low (not to zero) reading. When the throttle is suddenly released, the needle will snap back up to a higher than normal figure.

2.

3. NORMAL FOR HIGH-LIFT CAMSHAFT WITH LARGE OVERLAP: The needle will register as low as 51 kPa (15 in-Hg) but will be

relatively steady. Some oscillation is normal.

3.

4. WORN RINGS OR DILUTED OIL: When the engine is accelerated (dotted needle), the needle drops to 0 kPa (0 in-Hg). Upon

deceleration, the needle runs slightly above 74 kPa (22 in-Hg).

4.

5. STICKING VALVES: W hen the needle (dotted) remains steady at a normal vacuum but occasionally flicks (sharp, fast movement)

down and back about 13 kPa (4 in-Hg), one or more valves may be sticking.

5.

6. BURNED OR BENT VALVES: A regular, evenly-spaced, downscale flicking of the needle indicates one or more burned or damaged

valves. Insufficient hydraulic valve tappet or hydraulic lash adjuster clearance will also cause this reaction.

6.

7. POOR VALVE SEATING: A small but regular downscale flicking can mean one or more valves are not seating correctly.

7.

8. WORN VALVE GUIDES: When the needle oscillates over about a 13 kPa (4 in-Hg) range at idle speed, the valve guides could be

worn. As engine speed increases, the needle will become steady if guides are responsible.

8.

9. WEAK VALVE SPRINGS: W hen the needle oscillation becomes more violent as engine RPM is increased, weak valve springs are

9.

indicated. The reading at idle could be relatively steady.

10. LATE VALVE TIMING: A steady but low reading could be caused by late valve timing.

10.

11. IGNITION TIMING RETARDING: Retarded ignition timing will produce a steady but somewhat low reading.

11.

12. INSUFFICIENT SPARK PLUG GAP: When spark plugs are gapped too close, a regular, small pulsation of the needle can occur.

12.

13. INTAKE LEAK: A low, steady reading can be caused by an intake manifold or throttle body gasket leak.

13.

14. BLOW N HEAD GASKET: A regular drop of fair magnitude can be caused by a blown head gasket or warped cylinder head to

cylinder block surface.

14.

15. RESTRICTED EXHAUST SYSTEM: When the engine is first started and is idled, the reading may be normal, but as the engine rpm

is increased, the back pressure caused by a clogged muffler, kinked tail pipe or other concerns will cause the needle to slowly drop
to 0 kPa (0 in-Hg). The needle then may slowly rise. Excessive exhaust clogging will cause the needle to drop to a low point even
if the engine is only idling.

15.

When vacuum leaks are indicated, search out and correct the cause. Excess air leaking into the system will upset the fuel mixture and cause
concerns such as rough idle, missing on acceleration or burned valves. If the leak exists in an accessory such as the power brake booster,
the unit will not function correctly. Always repair vacuum leaks.

Published: 11-May-2011

Engine System - General Information - Bearing Inspection

General Procedures

1. Inspect bearings for the following defects.

1. Cratering - fatigue failure

2. Spot polishing - incorrect seating.

3. Imbedded dirt engine oil.

4. Scratching - dirty engine oil.

5. Base exposed - poor lubrication.

6. Both edges worn - journal damaged.

7. One edge worn - journal tapered or bearing not seated.