1988 OPEL VECTRA fuel consumption

HEI (High Energy Ignition)
system
5This comprises of a breakerless distributor
and an electronic switching/amplifier module
along with the coil and spark plugs.
6The electrical impulse that is required to
switch off the low tension circuit is generated
by a magnetic trigger coil in the distributor. A
trigger wheel rotates within a magnetic stator,
the magnetic field being provided by a
permanent magnet. The magnetic field across
the two poles (stator arm and trigger wheel) is
dependent on the air gap between the two
poles. When the air gap is at its minimum, the
trigger wheel arm is directly opposite the
stator arm, and this is the trigger point. As the
magnetic flux between the stator arm and
trigger wheel varies, a voltage is induced in the
trigger coil mounted below the trigger wheel.
This voltage is sensed and then amplified by
the electronic module, and used to switch off
the low tension circuit. There is one trigger arm
and one stator arm for each cylinder.
7The ignition advance is a function of the
distributor, and is controlled both
mechanically and by a vacuum-operated
system. The mechanical governor mechanism
consists of two weights that move out from
the distributor shaft due to centrifugal force as
the engine speed rises. As the weights move
outwards, they rotate the trigger wheel
relative to the distributor shaft and so
advance the spark. The weights are held in
position by two light springs, and it is the
tension of the springs that is largely
responsible for correct spark advancement.
8The vacuum control consists of a
diaphragm, one side of which is connected by
way of a small-bore hose to the carburettor,
and the other side to the distributor.
Depression in the inlet manifold and
carburettor, which varies with engine speed
and throttle position, causes the diaphragm to
move, so moving the baseplate and
advancing or retarding the spark. A fine
degree of control is achieved by a spring in
the diaphragm assembly.
MSTS-i (Microprocessor-
controlled Spark Timing System)
9This system comprises a “Hall-effect”
distributor (or a crankshaft speed/position
sensor on X 16 SZ models), a manifold pressure
sensor, an oil temperature sensor, and a
module, along with the coil and spark plugs.
10On 1.6 litre models, the electrical impulse
that is required to switch off the low tension
circuit is generated by a sensor in the
distributor. A trigger vane rotates in the gap
between a permanent magnet and the sensor.
The trigger vane has four cut-outs, one for
each cylinder. When one of the trigger vane
cut-outs is in line with the sensor, magnetic
flux can pass between the magnet and the
sensor. When a trigger vane segment is in line
with the sensor, the magnetic flux is diverted
through the trigger vane away from thesensor. The sensor senses the change in
magnetic flux, and sends an impulse to the
MSTS-i module, which switches off the low
tension circuit.
11On 1.8 litre models, the electrical impulse
that is required to switch off the low tension
circuit is generated by a crankshaft
speed/position sensor, which is activated by a
toothed wheel on the crankshaft. The toothed
wheel has 35 equally spaced teeth, with a gap
in the 36th position. The gap is used by the
sensor to determine the crankshaft position
relative to TDC (top dead centre) of No 1 piston.
12Engine load information is supplied to the
MSTS-i module by a pressure sensor, which
is connected to the carburettor by a vacuum
pipe. Additional information is supplied by an
oil temperature sensor. The module selects
the optimum ignition advance setting based
on the information received from the sensors.
The degree of advance can thus be constantly
varied to suit the prevailing engine conditions.
Multec, with MSTS-i
13The ignition system is fully electronic in
operation and incorporates the Electronic
Control Unit (ECU) mounted in the driver’s
footwell. A distributor (driven off the camshaft
left-hand end and incorporating the amplifier
module) as well as the octane coding plug,
the spark plugs, HT leads, ignition HT coil and
associated wiring.
14The ECU controls both the ignition system
and the fuel injection system, integrating the
two in a complete engine management
system. Refer to Chapters 4B and 4C for
further information that is not detailed here.
15For ignition the ECU receives information
in the form of electrical impulses or signals
from the distributor (giving it the engine speed
and crankshaft position), from the coolant
temperature sensor (giving it the engine
temperature) and from the manifold absolute
pressure sensor (giving it the load on the
engine). In addition, the ECU receives input
from the octane coding plug (to provide
ignition timing appropriate to the grade of fuel
used) and from, where fitted, the automatic
transmission control unit (to smooth gear
changing by retarding the ignition as changes
are made).
16All these signals are compared by the
ECU with set values pre-programmed
(mapped) into its memory. Considering this
information, the ECU selects the ignition
timing appropriate to those values and
controls the ignition HT coil by way of the
amplifier module accordingly.
17The system is so sensitive that, at idle
speed, the ignition timing may be constantly
changing; this should be remembered if trying
to check the ignition timing.
18The system fitted to C18 NZ models, is
similar to that described above, except that
the amplifier module is separate. The ECU
determines engine speed and crankshaft
position using a sensor mounted in the
right-hand front end of the engine’s cylinderblock; this registers with a 58-toothed disc
mounted on the crankshaft so that the gap left
by the missing two teeth provides a reference
point, so enabling the ECU to recognise TDC.
19Note that this simplifies the distributor’s
function, which is merely to distribute the HT
pulse to the appropriate spark plug; it has no
effect whatsoever on the ignition timing.
DIS (Direct Ignition System)
20On all X16 SZ engines, and on C20 XE
(DOHC) engines from 1993-on, a DIS (Direct
Ignition System) module is used in place of
the distributor and coil. On the X16 SZ engine
the DIS module is attached to the camshaft
housing in the position normally occupied by
the distributor. On the C20 XE engine, a
camshaft phase sensor is attached to the
cylinder head at the non-driven end of the
exhaust camshaft, in the position normally
occupied by the distributor. The DIS module
is attached, by a bracket, to the cylinder head
at the non-driven end of the inlet camshaft.
21The DIS module consists of two ignition
coils and an electronic control module housed
in a cast casing. Each ignition coil supplies
two spark plugs with HT voltage. One spark is
provided in a cylinder with its piston on the
compression stroke, and one spark is
provided to a cylinder with its piston on the
exhaust stroke. This means that a “wasted
spark” is supplied to one cylinder during each
ignition cycle, but this has no detrimental
effect. This system has the advantage that
there are no moving parts (therefore there is
no wear), and the system is largely
maintenance-free.
Motronic M4.1 and M1.5
22This system controls both the ignition and
the fuel injection systems.
23The Motronic module receives information
from a crankshaft speed/position sensor, an
engine coolant temperature sensor mounted
in the thermostat housing. A throttle position
sensor, an airflow meter, and on models fitted
with a catalytic converter, an oxygen sensor
mounted in the exhaust system (Chapter 4C).
24The module provides outputs to control
the fuel pump, fuel injectors, idle speed and
ignition circuit. Using the inputs from the
various sensors, the module computes the
optimum ignition advance, and fuel injector
pulse duration, to suit the prevailing engine
conditions. This system gives very accurate
control of the engine under all conditions,
improving fuel consumption and driveability,
and reducing exhaust gas emissions.
25Further details of the fuel injection system
components are given in Chapter 4B.
Motronic M2.5 and M2.8
26The system is similar to that described for
SOHC models, with the following differences.
27Along with the crankshaft speed/position
sensor, a “Hall-effect” distributor is used
(similar to that described in this Section, with
the MSTS-i system).
Engine electrical systems 5•3
5

b)Always keep the ignition and fuel systems
well maintained according to the
manufacturers schedule (see “Routine
maintenance” and the relevant Chapter).
In particular, ensure that the air cleaner
filter element, the fuel filter and the spark
plugs are renewed at the correct intervals.
If the inlet air/fuel mixture is allowed to
become too rich due to neglect, the
unburned surplus will enter and burn in
the catalytic converter, overheating the
element and eventually destroying the
converter.
c)If the engine develops a misfire, do not
drive the vehicle at all (or at least as little
as possible) until the fault is cured. The
misfire will allow unburned fuel to enter
the converter, which will result in its
overheating, as noted above.
d)The engine control indicator (the outline
of an engine with a lightning symbol
superimposed), will light when the ignition
is switched on and the engine is started,
then it will go out. While it may light briefly
while the engine is running, it should go
out again immediately and stays unlit. If it
lights and stays on while the engine is
running, seek the advice of a Vauxhall
dealer as soon as possible. A fault has
occurred in the fuel injection/ignition
system that, apart from increasing fuel
consumption and impairing the engine’s
performance, may damage the catalytic
converter.
e)DO NOT push or tow-start the vehicle.
This will soak the catalytic converter in
unburned fuel causing it to overheat when
the engine does start see (b) above.
f)DO NOT switch off the ignition at high
engine speeds. If the ignition is switched
off at anything above idle speed,
unburned fuel will enter the (very hot)
catalytic converter, with the possible risk
of its igniting on the element and
damaging the converter.
g)DO NOT use fuel or engine oil additives.
These may contain substances harmful to
the catalytic converter.
h)DO NOT continue to use the vehicle if the
engine burns oil to the extent of leaving a
visible trail of blue smoke. The unburned
carbon deposits will clog the converter
passages and reduce its efficiency; in
severe cases the element will overheat.
i)Remember that the catalytic converter
operates at very high temperatures hence
the heat shields on the vehicle’s under-
body and the casing will become hot
enough to ignite combustible materials
that brush against it. DO NOT, therefore,
park the vehicle in dry undergrowth, over
long grass or over piles of dead leaves.
j)Remember that the catalytic converter is
FRAGlLE. Do not strike it with tools during
servicing work. Take great care when
working on the exhaust system. Ensure
that the converter is well clear of any
jacks or other lifting gear used to raise thevehicle. Do not drive the vehicle over
rough ground, road humps, etc., in such a
way as to ground the exhaust system.
k)In some cases, particularly when the
vehicle is new and/or is used for
stop/start driving, a sulphurous smell (like
that of rotten eggs) may be noticed from
the exhaust. This is common to many
catalytic converter-equipped vehicles and
seems to be due to the small amount of
sulphur found in some petrol’s reacting
with hydrogen in the exhaust to produce
hydrogen sulphide (CS) gas. While this
gas is toxic, it is not produced in sufficient
amounts to be a problem. Once the
vehicle has covered a few thousand miles
the problem should disappear. In the
meanwhile a change of driving style or of
the brand of petrol may effect a solution.
l)The catalytic converter, used on a
well-maintained and well-driven vehicle,
should last for between 50 000 and 100
000 miles. From this point on, careful
checks should be made at all specified
service intervals of the CO level to ensure
that the converter is still operating
efficiently. If the converter is no longer
effective it must be renewed.
11Carbon canister - removal
and refitting
3
Removal
1Apply the handbrake, then jack up the front
of the vehicle, and support securely on axle
stands placed under the body side members
(see “Jacking and Vehicle Support”).
2Remove the front right hand wheel and
wheel arch liner.
3Note the hose and pipe connections to the
canister, or label them, to ensure that they are
reconnected to their original unions, then
disconnect them (see illustration). Unscrew
the two nuts securing the canister mounting
bracket to the vehicle body.
Refitting
4Refitting is a reversal of removal, however
ensure correct fitment of hose and pipes.
12Oxygen sensor (catalytic
converter models) - removal
and refitting
3
Note: This sensor is also known as a Lambda
sensor.
Removal
1Disconnect the battery negative lead.
2Disconnect the oxygen sensor wiring plug,
which is located behind the coolant expansion
tank.
3Apply the handbrake, then jack up the front
of the vehicle, and support securely on axle
stands placed under the body side members.
4On DOHC models, remove the engine
undershield, as described in Chapter 11.
5On models fitted with Multec injection
system, the sensor is screwed into the
exhaust manifold. Trace the wiring from the
sensor itself to the connector (either clipped
to the radiator cooling fan shroud or behind
the coolant expansion tank). Release it from
any clips or ties; disconnect the wiring before
unscrewing the sensor.
6On other models, unscrew the oxygen
sensor from the front section of the exhaust
system (see illustration). It is advisable to
wear gloves, as the exhaust system will be
extremely hot.
7Withdraw the oxygen sensor and its wiring,
taking care not to burn the wiring on the
exhaust system. If the sensor is to be re-used,
take care that the sealing ring is not lost, and
that the sensor is not dropped.
Refitting
8If a new sensor is being fitted, it will be
supplied with the threads coated in a special
grease to prevent it seizing in the exhaust
system.
9If the original sensor is being refitted,
ensure that the screw thread is clean. Coat
the thread with a lithium based copper grease
(i.e. Vauxhall Part No. 90295397).
10Refitting is a reversal of removal. Check
the exhaust system for leakage when the
engine is re-started.
4C•4Fuel and exhaust systems - exhaust and emissions
12.6 Oxygen sensor location in front
section of exhaust system - DOHC models
11.3 Charcoal canister
A Vent to atmosphere
B Vapour feed hose from filler pipe
C Vapour exhaust hose to inlet tract
D Control valve vacuum pipe from
throttle body

REF•2Conversion Factors
Length (distance)Inches (in) 25.4 = Millimetres (mm) x 0.0394 = Inches (in)
Feet (ft) 0.305 = Metres (m) x 3.281 = Feet (ft)
Miles 1.609 = Kilometres (km) x 0.621 = Miles
Volume (capacity)Cubic inches (cu in; in3) x 16.387 = Cubic centimetres (cc; cm3) x 0.061 = Cubic inches (cu in; in3)
Imperial pints (Imp pt) x 0.568 = Litres (l) x 1.76 = Imperial pints (Imp pt)
Imperial quarts (Imp qt) x 1.137 = Litres (l) x 0.88 = Imperial quarts (Imp qt)
Imperial quarts (Imp qt) x 1.201 = US quarts (US qt) x 0.833 = Imperial quarts (Imp qt)
US quarts (US qt) x 0.946 = Litres (l) x 1.057 = US quarts (US qt)
Imperial gallons (Imp gal) x 4.546 = Litres (l) x 0.22 = Imperial gallons (Imp gal)
Imperial gallons (Imp gal) x 1.201 = US gallons (US gal) x 0.833 = Imperial gallons (Imp gal)
US gallons (US gal) x 3.785 = Litres (l) x 0.264 = US gallons (US gal)
Mass (weight)Ounces (oz) x 28.35 = Grams (g) x 0.035 = Ounces (oz)
Pounds (lb) x 0.454 = Kilograms (kg) x 2.205 = Pounds (lb)
ForceOunces-force (ozf; oz) x 0.278 = Newtons (N) x 3.6 = Ounces-force (ozf; oz)
Pounds-force (lbf; lb) x 4.448 = Newtons (N) x 0.225 = Pounds-force (lbf; lb)
Newtons (N) x 0.1 = Kilograms-force (kgf; kg) x 9.81 = Newtons (N)
PressurePounds-force per square inch x 0.070 = Kilograms-force per square x 14.223 = Pounds-force per square inch
(psi; lbf/in2; lb/in2) centimetre (kgf/cm2; kg/cm2) (psi; lbf/in2; lb/in2)
Pounds-force per square inch x 0.068 = Atmospheres (atm) x 14.696 = Pounds-force per square inch
(psi; lbf/in
2; lb/in2)(psi; lbf/in2; lb/in2)
Pounds-force per square inch x 0.069 = Bars x 14.5 = Pounds-force per square inch
(psi; lbf/in
2; lb/in2)(psi; lbf/in2; lb/in2)
Pounds-force per square inch x 6.895 = Kilopascals (kPa) x 0.145 = Pounds-force per square inch
(psi; lbf/in
2; lb/in2)(psi; lbf/in2; lb/in2)
Kilopascals (kPa) x 0.01 = Kilograms-force per square x 98.1 = Kilopascals (kPa)
centimetre (kgf/cm
2; kg/cm2)
Millibar (mbar) x 100 = Pascals (Pa) x 0.01 = Millibar (mbar)
Millibar (mbar) x 0.0145 = Pounds-force per square inch x 68.947 = Millibar (mbar)
(psi; lbf/in
2; lb/in2)
Millibar (mbar) x 0.75 = Millimetres of mercury (mmHg) x 1.333 = Millibar (mbar)
Millibar (mbar) x 0.401 = Inches of water (inH
2O) x 2.491 = Millibar (mbar)
Millimetres of mercury (mmHg) x 0.535 = Inches of water (inH
2O) x 1.868 = Millimetres of mercury (mmHg)
Inches of water (inH
2O) x 0.036 = Pounds-force per square inch x 27.68 = Inches of water (inH2O)
(psi; lbf/in2; lb/in2)
Torque (moment of force)Pounds-force inches (lbf in; lb in) x 1.152 = Kilograms-force centimetre x 0.868 = Pounds-force inches (lbf in; lb in)
(kgf cm; kg cm)
Pounds-force inches (lbf in; lb in) x 0.113 = Newton metres (Nm) x 8.85 = Pounds-force inches (lbf in; lb in)
Pounds-force inches (lbf in; lb in) x 0.083 = Pounds-force feet (lbf ft; lb ft) x 12 = Pounds-force inches (lbf in; lb in)
Pounds-force feet (lbf ft; lb ft) x 0.138 = Kilograms-force metres (kgf m; kg m) x 7.233 = Pounds-force feet (lbf ft; lb ft)
Pounds-force feet (lbf ft; lb ft) x 1.356 = Newton metres (Nm) x 0.738 = Pounds-force feet (lbf ft; lb ft)
Newton metres (Nm) x 0.102 = Kilograms-force metres (kgf m; kg m) x 9.804 = Newton metres (Nm)
PowerHorsepower (hp) x 745.7 = Watts (W) x 0.0013 = Horsepower (hp)
Velocity (speed)Miles per hour (miles/hr; mph) x 1.609 = Kilometres per hour (km/hr; kph) x 0.621 = Miles per hour (miles/hr; mph)
Fuel consumption*Miles per gallon (mpg) x 0.354 = Kilometres per litre (km/l) x 2.825 = Miles per gallon (mpg)
* It is common practice to convert from miles per gallon (mpg) to litres/100 kilometres (l/100km), where mpg x l/100 km = 282
TemperatureDegrees Fahrenheit = (°C x 1.8) + 32 Degrees Celsius (Degrees Centigrade; °C) = (°F - 32) x 0.56

Engine
m mEngine fails to rotate when attempting to start
m mEngine rotates, but will not start
m mEngine difficult to start when cold
m mEngine difficult to start when hot
m mStarter motor noisy or excessively rough in engagement
m mEngine starts, but stops immediately
m mEngine idles erratically
m mEngine misfires at idle speed
m mEngine misfires throughout the driving speed range
m mEngine hesitates on acceleration
m mEngine stalls
m mEngine lacks power
m mEngine backfires
m mOil pressure warning light illuminated with engine running
m mEngine runs-on after switching off
m mEngine noises
Cooling system
m
mOverheating
m mOvercooling
m mExternal coolant leakage
m mInternal coolant leakage
m mCorrosion
Fuel and exhaust systems
m
mExcessive fuel consumption
m mFuel leakage and/or fuel odour
m mExcessive noise or fumes from exhaust system
Clutch
m
mPedal travels to floor - no pressure or very little resistance
m mClutch fails to disengage (unable to select gears)
m mClutch slips (engine speed increases, with no increase in vehicle
speed)
m mJudder as clutch is engaged
m mNoise when depressing or releasing clutch pedal
Manual transmission
m
mNoisy in neutral with engine running
m mNoisy in one particular gear
m mDifficulty engaging gears
m mJumps out of gear
m mVibration
m mLubricant leaks
Automatic transmission
m
mFluid leakage
m mTransmission fluid brown, or has burned smell
m mGeneral gear selection problems
m mTransmission will not downshift (kickdown) with accelerator fully
depressed
m mEngine will not start in any gear, or starts in gears other than Park
or Neutral
m mTransmission slips, shifts roughly, is noisy, or has no drive in
forward or reverse gears
Driveshafts
m mClicking or knocking noise on turns (at slow speed on full-lock)
m mVibration when accelerating or decelerating
Braking system
m
mVehicle pulls to one side under braking
m mNoise (grinding or high-pitched squeal) when brakes applied
m mExcessive brake pedal travel
m mBrake pedal feels spongy when depressed
m mExcessive brake pedal effort required to stop vehicle
m mJudder felt through brake pedal or steering wheel when braking
m mBrakes binding
m mRear wheels locking under normal braking
Suspension and steering systems
m
mVehicle pulls to one side
m mWheel wobble and vibration
m mExcessive pitching and/or rolling around corners, or during
braking
m mWandering or general instability
m mExcessively stiff steering
m mExcessive play in steering
m mLack of power assistance
m mTyre wear excessive
Electrical system
m
mBattery will not hold a charge for more than a few days
m mIgnition/no-charge warning light remains illuminated with engine
running
m mIgnition/no-charge warning light fails to come on
m mLights inoperative
m mInstrument readings inaccurate or erratic
m mHorn inoperative, or unsatisfactory in operation
m mWindscreen/tailgate wipers inoperative, or unsatisfactory in
operation
m mWindscreen/tailgate washers inoperative, or unsatisfactory in
operation
m mElectric windows inoperative, or unsatisfactory in operation
m mCentral locking system inoperative, or unsatisfactory in operation
The vehicle owner who does his or her own maintenance according to
the recommended service schedules should not have to use this section
of the manual very often. Modern component reliability is such that,
provided those items subject to wear or deterioration are inspected or
renewed at the specified intervals, sudden failure is comparatively rare.
Faults do not usually just happen as a result of sudden failure, but
develop over a period of time. Major mechanical failures in particular are
usually preceded by characteristic symptoms over hundreds or even
thousands of miles. Those components that do occasionally fail without
warning are often small and easily carried in the vehicle.
With any fault-finding, the first step is to decide where to begininvestigations. Sometimes this is obvious, but on other occasions, a
little detective work will be necessary. The owner who makes half a
dozen haphazard adjustments or replacements may be successful in
curing a fault (or its symptoms). However, will be none the wiser if the
fault recurs, and ultimately may have spent more time and money than
was necessary. A calm and logical approach will be found to be more
satisfactory in the long run. Always take into account any warning
signs or abnormalities that may have been noticed in the period
preceding the fault - power loss, high or low gauge readings, unusual
smells, etc. - and remember that failure of components such as fuses
or spark plugs may only be pointers to some underlying fault.
REF•12Fault Finding
Introduction

Excessive fuel consumption
MAir filter element dirty or clogged (Chapter 1).
MChoke cable incorrectly adjusted, or choke sticking - carburettor
models (Chapter 4A).
MFuel injection system fault - fuel-injected models (Chapter 4B).
MIgnition timing incorrect/ignition system fault (Chapters 1 and 5).
MTyres under-inflated (Chapter 1).
Fuel leakage and/or fuel odour
MDamaged or corroded fuel tank, pipes or connections (Chapter 4A
or 4B).
MCarburettor float chamber flooding (float height incorrect) -
carburettor models (Chapter 4A).
Excessive noise or fumes from exhaust system
MLeaking exhaust system or manifold joints (Chapters 1 and 4C).
MLeaking, corroded or damaged silencers or pipe (Chapters 1 and 4C).
MBroken mountings causing body or suspension contact (Chapter 1).
Pedal travels to floor - no pressure or very little
resistance
MBroken clutch cable (Chapter 6).
MIncorrect clutch cable adjustment (Chapter 6).
MBroken clutch release bearing or fork (Chapter 6).
MBroken diaphragm spring in clutch pressure plate (Chapter 6).
Clutch fails to disengage (unable to select gears).
MIncorrect clutch cable adjustment (Chapter 6).
MClutch disc sticking on transmission input shaft splines (Chapter 6).
MClutch disc sticking to flywheel or pressure plate (Chapter 6).
MFaulty pressure plate assembly (Chapter 6).
MClutch release mechanism worn or incorrectly assembled (Chapter 6).
Clutch slips (engine speed increases, with no
increase in vehicle speed).
MIncorrect clutch cable adjustment (Chapter 6).
MClutch disc linings excessively worn (Chapter 6).MClutch disc linings contaminated with oil or grease (Chapter 6).
MFaulty pressure plate or weak diaphragm spring (Chapter 6).
Judder as clutch is engaged
MClutch disc linings contaminated with oil or grease (Chapter 6).
MClutch disc linings excessively worn (Chapter 6).
MClutch cable sticking or frayed (Chapter 6).
MFaulty or distorted pressure plate or diaphragm spring (Chapter 6).
MWorn or loose engine or transmission mountings (Chapter 2A or 2B).
MClutch disc hub or transmission input shaft splines worn (Chapter 6).
Noise when depressing or releasing clutch pedal
MWorn clutch release bearing (Chapter 6).
MWorn or dry clutch pedal bushes (Chapter 6).
MFaulty pressure plate assembly (Chapter 6).
MPressure plate diaphragm spring broken (Chapter 6).
MBroken clutch disc cushioning springs (Chapter 6).
Fault Finding REF•15
REF
Overheating
MInsufficient coolant in system (Chapter 1).
MThermostat faulty (Chapter 3).
MRadiator core blocked, or grille restricted (Chapter 3).
MElectric cooling fan or thermoswitch faulty (Chapter 3).
MPressure cap faulty (Chapter 3).
MIgnition timing incorrect/ignition system fault (Chapters 1 and 5).
MInaccurate temperature gauge sender unit (Chapter 3).
MAirlock in cooling system (Chapter 1).
Overcooling
MThermostat faulty (Chapter 3).
MInaccurate temperature gauge sender unit (Chapter 3).
External coolant leakage
MDeteriorated or damaged hoses or hose clips (Chapter 1).
MRadiator core or heater matrix leaking (Chapter 3).
MPressure cap faulty (Chapter 3).
MWater pump seal leaking (Chapter 3).
MBoiling due to overheating (Chapter 3).
MCore plug leaking (Chapter 2A).
Internal coolant leakage
MLeaking cylinder head gasket (Chapter 2A or 2B).
MCracked cylinder head or cylinder bore (Chapter 2A or 2B).
Corrosion
MInfrequent draining and flushing (Chapter 1).
MIncorrect coolant mixture or inappropriate coolant type (Chapter 1).
Cooling system
Clutch
Fuel and exhaust systems