wheel bolt torque JAGUAR XFR 2010 1.G Workshop Manual
[x] Cancel search | Manufacturer: JAGUAR, Model Year: 2010, Model line: XFR, Model: JAGUAR XFR 2010 1.GPages: 3039, PDF Size: 58.49 MB
Page 72 of 3039
General Information - Standard Workshop Practices
Description and Operation
Protecting the Vehicle Published: 04-Jul-2014
Always install covers to protect the fenders before commencing work in the engine compartment. Always install the interior
protection kit, wear clean overalls and wash hands or wear gloves before working inside the vehicle. Avoid spilling hydraulic
fluid, antifreeze or battery acid on the paintwork. In the event of spillage, wash off with water immediately. Use polythene
sheets in the luggage compartment to protect carpets. Always use the recommended service tool, or a satisfactory equivalent,
where specified. Protect temporarily exposed screw threads by replacing nuts or installing caps.
Vehicle in Workshop
When working on a vehicle in the workshop always make sure that:
The parking brake is applied or the wheels are securely chocked to prevent the vehicle moving forwards or backwards
If the engine is to be run, there is adequate ventilation, or an extraction hose to remove exhaust fumes is installed
There is adequate room to jack up the vehicle and remove the wheels, if necessary
Fender covers are always installed if any work is to be carried out in the engine compartment
The battery is disconnected if working on the engine, underneath the vehicle, or if the vehicle is jacked up
CAUTION: When electric arc welding on a vehicle, always disconnect the generator wiring to prevent the possibility of a
surge of current causing damage to the internal components of the generator.
If using welding equipment on the vehicle, ensure a suitable fire extinguisher is readily available.
Screw Threads
Damaged nuts, bolts and screws must always be discarded. Attempting to recut or repair damaged threads with a tap
or die impairs the strength and fit of the threads and is not recommended.
NOTES:
During certain repair operations, it may be necessary to remove traces of thread locking agents using a tap. Where this
is necessary, the instruction to do so will appear in the relevant operation and it is essential that a tap of the correct size and
thread is used.
New Taptite bolts when used cut their own threads on the first application.
Some bolts are coated with a thread locking agent and unless stated otherwise, they must not be reused. New bolts
having the same part number as the original must always be installed. When nuts or bolts are to be discarded, the
repair operation and relevant torque chart will include an instruction to that effect. Do not use proprietary thread
locking agents as they may not meet the specification required. See also Encapsulated ('Patched') Bolts and Screws.
Always make sure that replacement nuts and bolts are at least equal in strength to those that they are replacing.
Castellated nuts must not be loosened to accept a split pin except in recommended cases when this forms part of an
adjustment.
Do not allow oil or grease to enter blind holes, the hydraulic action resulting from tightening the bolt or stud can split
the housing and also give a false torque reading.
Always tighten a nut, bolt or screw to the specified torque figure, damaged or corroded threads can give a false torque
reading.
Nut and bolt loosening and tightening sequences, where given, must ALWAYS be followed. Distortion of components or
faulty sealing of joints will result if the sequences are not followed. Where an instruction is given to tighten in stages,
these stages must be adhered to; do not attempt to combine stages particularly where certain stages involve
tightening by degrees.
To check or re-tighten a fixing to a specified torque, first loosen a quarter of a turn, then retighten to the specified
torque figure.
Unless instructed otherwise, do not lubricate bolt or nut threads prior to installing.
Where it is stated that bolts and screws may be reused, the following procedures must be carried out:
Check that threads are undamaged.
Remove all traces of locking agent from the threads.
CAUTION: DO NOT use a wire brush; take care that threads are not damaged.
Make sure that threads are clean and free from oil or grease.
Apply the specified locking agent to the bolt threads.
Page 190 of 3039
DTC Description Possible Causes Action Battery voltage at electric
steering column lock control
module too low
Electric steering column lock
control module, instrument
cluster, central junction box
fault with the road wheel against a curb. If the
column lock is failing to disengage, the customer
may be able to rectify this by rotating the
steering wheel while pressing the engine start
button
If fault persists, complete a CAN network
integrity test using the manufacturers approved
diagnostic system. Alternatively, refer to the
electrical circuit diagrams and check CAN circuits
between the central junction box, the instrument
cluster and the electronic steering column lock.
Refer to the electrical circuit diagrams and check
the central junction box, the instrument cluster
and the electronic steering column lock power
and ground supply circuits for short circuit to
ground, short circuit to power, open circuit, high
resistance. Repair circuit(s) as required. Clear
DTC, perform an on demand self-test and retest
If fault persists, check that the vehicle battery
supply voltage is between 9-16 volts. Rectify as
required B100D-96
Column Lock
Authorisation -
Component internal
failure
Battery voltage at electric
steering column lock control
module too low
Torque load on steering
column
CAN fault
Electric steering column lock
control module - Internal
failure
Clear DTC, repeatedly lock and unlock car using
the key fob and retest
If fault persists, check that the vehicle battery
supply voltage is between 9-16 volts. Rectify as
required
Ensure the column lock bolt movement is not
obstructed or restricted (the parked position of
the road wheels may be exerting a turning force
through the steering column, preventing the lock
from releasing. The steering wheel may need to
be held against the force to allow the column
lock to release). Clear DTC, repeatedly lock and
unlock car using the key fob and retest
If fault persists, complete a CAN network
integrity test using the manufacturers approved
diagnostic system. Alternatively, refer to the
electrical circuit diagrams and check CAN circuits
between the central junction box, the instrument
cluster and the electronic steering column lock.
Refer to the electrical circuit diagrams and check
the central junction box, the instrument cluster
and the electronic steering column lock power
and ground supply circuits for short circuit to
ground, short circuit to power, open circuit, high
resistance. Repair circuit(s) as required. Clear
DTC, perform an on demand self-test and retest
If fault persists, check and install a new electric
steering column lock control module as required B1024-87
Start Control Unit -
Missing message
Smart card docking station
failure - slave node not
responding
Carry out any pinpoint tests associated with this
DTC using the manufacturer approved diagnostic
system. Refer to the electrical circuit diagrams
and check the smart card docking station LIN
circuit for short, open circuit. Suspect the smart
card docking station, check and install a new
docking station as required, refer to the new
module/component installation note at the top
of the DTC Index B1046-11
Front Fog Lamp Control
Switch - Circuit short to
ground
Fog lamp switch circuit -
short to ground
Refer to the electrical circuit diagrams and check
fog lamp switch circuit for short to ground B1046-15
Front Fog Lamp Control
Switch - Circuit short to
battery or open
Fog lamp switch circuit -
short to power, open circuit
Refer to the electrical circuit diagrams and check
fog lamp switch circuit for short to power, open
circuit B1048-11 Brake Fluid Level Switch
- Circuit short to ground
Brake fluid level switch
circuit - short to ground
Refer to the electrical circuit diagrams and check
brake fluid level switch circuit for short to ground
Page 301 of 3039
it may turn out to be the most important.
2. Do not touch anything until a road test and a thorough visual inspection of the vehicle have been carried out. Leave the
tire pressures and vehicle load just where they were when the condition was first observed. Adjusting tire pressures,
vehicle load or making other adjustments may reduce the conditions intensity to a point where it cannot be identified
clearly. It may also inject something new into the system, preventing correct diagnosis.
3. Make a visual inspection as part of the preliminary diagnosis routine, writing down anything that does not look right.
Note tire pressures, but do not adjust them yet. Note leaking fluids, loose nuts and bolts, or bright spots where
components may be rubbing against each other. Check the luggage compartment for unusual loads.
4. Road test the vehicle and define the condition by reproducing it several times during the road test.
5. Carry out the Road Test Quick Checks as soon as the condition is reproduced. This will identify the correct diagnostic
procedure. Carry out the Road Test Quick Checks more than once to verify they are providing a valid result. Remember,
the Road Test Quick Checks may not tell where the concern is, but they will tell where it is not.
Road Test Quick Checks
1. 24-80 km/h (15-50 miles/h): With light acceleration, a moaning noise is heard and possibly a vibration is felt in the
front floor pan. It is usually worse at a particular engine speed and at a particular throttle setting during acceleration at
that speed. It may also produce a moaning sound, depending on what component is causing it. Refer to Tip-In Moan in
the Symptom Chart.
2. Acceleration/deceleration: With slow acceleration and deceleration, a shake is sometimes noticed in the steering
wheel/column, seats, front floor pan, front door trim panel or front end sheet metal. It is a low frequency vibration
(around 9-15 cycles per second). It may or may not be increased by applying brakes lightly. Refer to Idle Boom/Shake
/Vibration in the Symptom Chart.
3. High speed: A vibration is felt in the front floor pan or seats with no visible shake, but with an accompanying sound or
rumble, buzz, hum, drone or booming noise. Coast with the clutch pedal depressed or shift control selector lever in
neutral and engine idling. If vibration is still evident, it may be related to wheels, tires, front brake discs, wheel hubs
or front wheel bearings. Refer to High Speed Shake in the Symptom Chart.
4. Engine rpm sensitive: A vibration is felt whenever the engine reaches a particular rpm. It will disappear in neutral
coasts. The vibration can be duplicated by operating the engine at the problem rpm while the vehicle is stationary. It
can be caused by any component, from the accessory drive belt to the torque converter which turns at engine speed
when the vehicle is stopped. Refer to High Speed Shake in the Symptom Chart.
5. Noise/vibration while turning: Clicking, popping, or grinding noises may be due to a worn, damaged, or incorrectly
installed front wheel bearing, rear drive half shaft or CV joint.
6. Noise/vibration that is road speed relative: This noise/vibration can be diagnosed independent of engine speed or gear
selected (engine speed varies but torque and road speed remain constant). The cause may be a rear drive
axle/differential whine.
Road Conditions
An experienced technician will always establish a route that will be used for all NVH diagnosis road tests. The road selected
should be reasonably smooth, level and free of undulations (unless a particular condition needs to be identified). A smooth
asphalt road that allows driving over a range of speeds is best. Gravel or bumpy roads are unsuitable because of the additional
road noise produced. Once the route is established and consistently used, the road noise variable is eliminated from the test
results.
NOTE: Some concerns may be apparent only on smooth asphalt roads.
If a customer complains of a noise or vibration on a particular road and only on a particular road, the source of the concern
may be the road surface. If possible, try to test the vehicle on the same type of road.
Vehicle Preparation
Carry out a thorough visual inspection of the vehicle before carrying out the road test. Note anything which is unusual. Do not
repair or adjust any condition until the road test is carried out, unless the vehicle is inoperative or the condition could pose a
hazard to the technician.
After verifying the condition has been corrected, make sure all components removed have been installed.
Lift Test
After a road test, it is sometimes useful to do a similar test on a lift.
When carrying out the high-speed shake diagnosis or engine accessory vibration diagnosis on a lift, observe the following
precautions:
WARNING: If only one drive wheel is allowed to rotate, speed must be limited to 55 km/h (35 miles/h) indicated on the
speedometer since actual wheel speed will be twice that indicated on the speedometer. Speed exceeding 55 km/h (35 miles/h)
or allowing the drive wheel to hang unsupported could result in tire disintegration, differential failure, constant velocity joint
Page 375 of 3039
7. CAUTIONS:
Discard the bolts.
Make sure that the area around the component is
clean and free of foreign material.
Do not attempt to release the wheel hub by hitting it
with a hammer directly, loosen the wheel hub retaining
bolts partially before applying an even amount of force to
the head of each bolts to release the wheel hub from the
wheel knuckle. Failure to follow this instruction may cause
damage to the component.
NOTES:
Some variation in the illustrations may occur, but the
essential information is always correct.
LH illustration shown, RH is similar.
Install the components to their original fitted
positions.
Torque: 90 Nm
Installation
1. To install, reverse the removal procedure. www.JagDocs.com
Page 536 of 3039
60 Oil seal The multi-plate clutch is contained in a clutch basket attached to the differential carrier with the crown wheel securing bolts.
Alternate plates of the clutch pack are keyed to the clutch basket and the LH sun gear. A pressure disc is installed on the outer end of the clutch pack and keyed to the clutch basket. A thrust race on the end of the clutch basket incorporates lugs which
extend through the clutch basket onto the pressure disc.
The actuator assembly is mounted on bearings on the outboard end of the clutch basket, against the thrust race. The actuator
assembly consists of input and output actuators separated by five ball bearings. A locking pin in the cover engages with a slot
in the output actuator to prevent it turning, but allow it to move axially. The input actuator engages with the reduction gearbox
and is free to rotate relative to the cover. Ball bearings locate in curved grooves in the mating faces of the input and
output actuators. The bottom surface of each groove incorporates a ramp. Rotation of the input actuator forces the ball
bearings up the ramps in the grooves and induces an axial movement in the output actuator. The thrust race and pressure disc
transfer the axial movement from the output actuator to the clutch pack.
Item Description 1 Actuator 2 Multi-plate clutch 3 Differential The motor is a 12 V dc motor that adjusts the frictional loading of the multi-plate clutch, via the reduction gearbox and the
actuator assembly, under the control of the DLM. Adjusting the frictional loading of the multi-plate clutch adjusts the locking
torque between the crown wheel drive gear and the sun wheel.
Four bolts attach the motor to the reduction gearbox, which is located in position on the cover with two dowels, and secured
with four bolts. An O-ring seals the joint between the motor and the reduction gearbox.
The motor is driven by a 12 V dc feed direct from the DLM. The motor also incorporates the following connections with the
DLM:
A motor temperature sensor, to prevent excessive use from damaging the motor.
Two Hall effect motor position sensors, to enable closed loop control of the motor.
The temperature sensor provides a differential oil temperature signal to the DLM, to prevent excessive use from damaging the
multi-plate clutch.
Differential Locking Module (DLM)
The DLM controls operation of the electronic differential. The DLM is attached to a bracket located on the LH side of the luggage compartment, immediately forward of the fender tail lamp, behind the trim.
Page 690 of 3039
Brake fluid Shell ESL Dot 4 Torque Specifications
Description Nm lb-ft lb-in Brake master cylinder primary pressure transducer 30 22 – Brake tubes to hydraulic control unit (HCU) 17 13 – Rear wheel speed sensor retaining bolt 6 – 53 Yaw rate sensor and accelerometer retaining nuts 7 – 62 Hydraulic control unit (HCU) retaining bolts 8 – 71 Steering wheel rotation sensor retaining screws 4 – 35 Steering column to lower shroud retaining screws 3 – 27 www.JagDocs.com
Page 719 of 3039
Symptom Possible Causes Action
Damaged fluid
cap/reservoir
Check and install a new fluid cap/reservoir as required
Loose or damaged
hoses and fittings
O-ring or Dowty seals
Tighten the hose connection or latch plate fixing to the
recommended torque.
REFER to: Specifications (211-00 Steering System - General Information, Specifications).
Check and install new components as required
Install new O-ring or Dowty seals as required
Fluid cooler
Check and install a new fluid cooler as required, refer to the new
module/component installation note at the top of the Symptom
Charts
Power steering pump
Check and install a new power steering pump as required, refer to
the new module/component installation note at the top of the
Symptom Charts Functional
Symptom Possible Causes Action
Steering wheel
misalignment
Steering not correctly centred
Check the steering alignment.
REFER to: Specifications (204-00 Suspension System - General
Information, Specifications).
Excessive free play at
steering wheel (refer to
the Steering Linkage
Inspection and Backlash
(Free play) Check in this
section)
Steering wheel loose
Check and tighten the steering
wheel retaining bolt as required.
REFER to: Specifications (211-00 Steering System - General
Information, Specifications).
Excess play in the steering linkage
Check and install new
components as required
Steering gear not correctly adjusted (causing
excessive backlash)
CAUTION: DO NOT attempt to
adjust the steering gear yoke. Failure to
follow this instruction will invalidate the
steering gear warranty
Check and install a new steering
gear as required, refer to the
new module/component
installation note at the top of
the Symptom Charts
Lower steering column universal joint pinch
bolts loose
Check and tighten the lower
steering column pinch bolts as
required.
REFER to: Specifications (211-00 Steering System - General
Information, Specifications).
Excessive wear in steering column universal
joints
Check and install a new steering
column or steering column lower
shaft as required, refer to the
new module/component
installation note at the top of
the Symptom Charts
Steering gear mounting bolts loose or
damaged
Check/tighten and install new
steering gear mounting bolts as
required.
REFER to: Specifications (211-00 Steering System - General
Information, Specifications). www.JagDocs.com
Page 722 of 3039
Noise
Symptom Possible Causes Action
Continuous noise
Low power steering fluid level
Check for leaks and rectify as required. For further
information refer to the symptom charts for
leakage in this section. Fill power steering fluid
reservoir to correct level
NOTE: Look for small air bubbles
visible in the fluid, air may also get
trapped in the hydraulic system
Air in hydraulic system
Bleed the power steering system.
REFER to: Power Steering System Bleeding (211-00 Steering System - General Information,
General Procedures).
Power steering pipe/hose in
contact with the vehicle body
Check and reposition, or install new IF
damaged/deformed, power steering pipe/hose
Power steering pipe/hose
restricted or twisted
Check and clear restriction to pipe/hose
Reposition power steering pipe/hose. Install new
pipe/hose IF permanently damaged/deformed
Power steering pump mounting
bolts loose
Tighten the power steering pump mounting bolts
to the correct torque.
REFER to: Specifications (211-00 Steering System - General Information, Specifications).
Noise gets worse
when system is
loaded
NOTE: Refer to the power
steering pressure check in this section
Low power steering fluid level
Aerated fluid
Low power steering pump
pressure
Check and fill power steering fluid reservoir to
correct level
Bleed the power steering system.
REFER to: Power Steering System Bleeding (211-00 Steering System - General Information,
General Procedures).
Check power steering pump pressure. If the pump
pressure is low, install a new power steering
pump
Front End Accessory
Drive (FEAD) belt
squeal
FEAD belt incorrectly tensioned
or glazed
Check FEAD belt tension
Check FEAD belt condition and install a new belt
as required
Chirp noise from the
steering pump when a
load is applied
Loose or worn FEAD belt
Check FEAD belt tension
Check FEAD belt condition and install a new belt
as required
Scrape/grind noise
from behind steering
wheel while steering
Steering column shroud foul
condition or clockspring
Correctly install the steering column shroud to
eliminate the foul condition
Install a new clockspring as required
Foreign objects
Remove foreign objects from between steering
column shroud and steering wheel/steering
column rotating components
Click
Clockspring or steering column
multifunction switch LH
Correctly install and install new components as
required
Loose universal joint pinch bolt
Install a new universal joint pinch bolt and
tighten to correct specification.
REFER to: Specifications (211-00 Steering System - General Information, Specifications).
Squeak
Steering column shroud joints
Apply Krytox spray to steering column shroud
joints
Clockspring
Install new clockspring as required
Page 782 of 3039
16 Ball (12 off) 17 Distance keeper 18 Crash tube The column comprises a cast magnesium mounting bracket which provides the attachment to the cross-beam. Attached to the
mounting bracket is a rake lever which is attached to the mounting bracket at the lower end with two pivot bearings. The
bearings allow the rake lever to rotate upwards or downward to adjust the column rake.
The rake lever also provides for the attachment of the rake housing which can slide within the lever to provide the reach
adjustment. Within the rake housing is the axial housing which is supported on each side with 6 ball bearings which allow the
rake housing to move forward or backwards. The bearings on each side are arranged in groups of 3 bearings and are separated
by a distance keeper which allows the housing to supported on bearings along its length. Within the axial housing is a tube
which is supported at the upper end of the column on the upper bearing. The tube has a central splined hole which provides for
the fitment of the splined shaft. The splined shaft can slide within the tube on the splines when the column reach is adjusted
or the column collapses in a crash condition. The splined shaft also passes rotary motion from the steering wheel through the
length of the column to the outer clamping yoke which is supported on the lower bearing.
The electric steering column lock is attached to the top of the rake lever. A lock bolt within the steering column lock engages in
one of 8 slots in the locking sleeve located at the lower end of the column preventing rotation of the steering wheel. The
locking sleeve is retained by a tolerance ring which in turn is located on the outer diameter of the tube yoke. The tolerance
ring allows a specified amount of torque to be applied to the splined shaft before it slips, preventing damage to the column
lock due to excessive force being applied to the steering wheel when the lock is engaged. The tolerance ring is designed to
slip on the splined shaft when the applied torque exceeds the fitted slip load of 200 Nm minimum. Repeated rotation of the
lock collar will reduce its slipping torque to 100 Nm minimum. The lock is controlled by the CJB.
A steering angle sensor is located at the upper end of the steering column and is attached to the crash adaptor. The sensor
measures steering rotation via a toothed wheel located on the splined tube at the upper end of the column. The sensor
receives a power supply from the CJB and supplies 2 signals (A and B) relating to the steering rotation to the ABS (anti-lock brake system) module. The module transmits this data on the high speed CAN bus for use by other vehicle systems. Refer to: Anti-Lock Control - Stability Assist (206-09 Anti-Lock Control - Stability Assist, Description and Operation).
The steering column is adjustable electrically, for reach and rake. The adjustment mechanism comprises an electric adjustment
motor, a lead screw, a rake solenoid, a reach solenoid, a reach clutch and a rake clutch. The column adjustment is controlled
manually using a joystick switch located on the LH (left-hand) side of the column lower cowl. The joystick can be moved
forward and backward to adjust the column reach in and out and moved up and down to adjust the rake. The switch selection
energizes the adjustment motor in the applicable direction and also engages the applicable solenoid and clutch.
When the joystick switch is rotated to the 'auto' position, the steering column will adjust to the uppermost rake position when
the ignition is switched off. It will re-adjust to the position corresponding to the memory position for the remote handset when
the ignition is switched on.
The memory function of the electric column is linked to and controlled by the driver's seat module. The module provides for the
storage of three separate memory positions which are stored against 3 individual remote handsets.
Refer to: Seats (501-10 Seating, Description and Operation).
The steering wheel locates on a splined shaft in the upper column assembly and is secured with a bolt. The steering wheel
houses the driver's airbag and switches for the audio system, gear change and speed control. A clockspring is used to connect
the steering wheel electrical components to the vehicle harness.
Two plastic shrouds are fitted to the upper column assembly. The lower shroud is fitted with an energy absorbing foam pad to
minimize leg injury in the event of an accident.
www.JagDocs.com
Page 813 of 3039
Component Tests
Engine Oil Leaks
NOTE: Before installing new gaskets or oil seals, make sure that the fault is clearly established.
If the oil leak cannot be identified clearly by a visual inspection, carry out an Ultraviolet test:
Fluorescent Oil Additive Method
1. Clean the engine with a suitable cleaning fluid (brake cleaner).
2. Drain the engine oil and refill with recommended oil, premixed with Diesel Engine Oil Dye or equivalent. Use a minimum
14.8 ml (0.5 ounce) to a maximum 29.6 ml (1 ounce) of fluorescent additive to all engines. If oil is not premixed,
fluorescent additive must first be added to the crankcase.
3. Run engine for 15 minutes. Stop the engine and inspect all seal and gasket areas for leaks using a 12 Volt Master UV
Diagnostic Inspection Kit or equivalent. A clear bright yellow or orange area will identify leak. For extremely small
leaks, several hours may be required for the leak to appear.
4. As necessary, pressurize the main oil gallery system to locate leaks due to incorrectly sealed, loose or cocked plugs. If
the flywheel bolts leak oil, look for sealer on the threads.
5. Repair all leaks as necessary.
Compression Test General Remarks
NOTES:
Removing fuses and disconnecting electrical components may cause the Engine Control Module (ECM) to log Diagnostic
Trouble Codes (DTCs). After the measurements have been carried out, DTCs should be cleared from memory by connecting to
the Manufacturer Approved Diagnostic System.
Only check the compression pressure with the valves set to the prescribed clearance (if this can be adjusted).
The compression pressure should be checked with the engine at normal operating temperature.
Check the Compression Pressure
WARNING: Move gear selector lever to 'P' position. Failure to follow this instruction may result in personal injury.
1. Remove the fuel pump relay.
2. Start the engine - the engine will start, run for a few seconds then stall.
3. Remove the spark plugs.
4. Install the compression tester.
5. Install an auxiliary starter switch in the starting circuit. With the ignition switch OFF, using the auxiliary starter switch,
crank the engine a minimum of five compression strokes and record the highest reading. Note the approximate number
of compression strokes required to obtain the highest reading.
6. Repeat the test on each cylinder, cranking the engine approximately the same number of compression strokes.
7. Install the removed components in reverse order, observing the specified tightening torques.
8. Clear all DTCs from the ECM.
Interpretation of the Results
NOTE: Due to the possibility of loose carbon that has become trapped between the valve face and seat effecting the
pressure readings, when carrying out a compression test and cylinders are found to have low pressures, install the spark plugs,
road test the vehicle and re-test the suspect cylinders. If the correct pressures are restored, no further action is required.
The indicated compression pressures are considered within specification if the lowest reading cylinder is within 75% of the
highest reading.
If the cylinder pressures are found to be low, carry out a leakdown test to determine the location of the fault (if any leakback
can be heard through the engine breather system suspect the piston rings, if any leakback can be heard through the inlet
system suspect the inlet valve or seat, if any leakback can be heard through the exhaust manifold suspect the exhaust valve
or seat. 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