1988 OPEL VECTRA warning light

Wiring diagrams 12•57
12
Key to wiring diagrams for 1992 and later models (continued)
NoDescriptionTrackNoDescriptionTrack
S20.2High pressure compressor switch925
S20.3High pressure blower compressor switch939
S21Fog lamps switch555 to 557
S22Rear fog lamp switch549 to 551
S24Air conditioning blower switch904 to 911
S29Coolant temperature switch118, 137, 357, 942, 957, 972
S30Left front heating mat switch660 to 662
S31Rear left door contact switch591
S32Rear right door contact switch592
S33Traction control switch1130, 1131
S37Window lifter switch868 to 894
S37.1Left window lifter switch868 to 870
S37.2Right window lifter switch886 to 888
S37.3Left rear window lifter switch874 to 876
S37.4Right rear window lifter switch892 to 894
S37.5Safety switch872, 873
S37.6Window anti-jam off switch890
S37.7Automatic window lifter control877 to 882
S39Left rear door window lifter switch878 to 880
S40Right rear door window lifter switch896 to 898
S41Driver door burglary locking switch800 to 802
S42Passenger door central locking switch805
S44Throttle valve switch316, 317
S47Driver door contact switch593, 594
S52Hazard warning switch569 to 573
S53First gear identification switch372
S55Right front heating mat switch664 to 666
S57Sun roof switch1170 to 1183
S63Computer switch
S63.1Function reset switch856
S63.2Clock hours adjustment switch857
S63.3Function select switch858
S63.4Clock minute adjustment switch859
S64Horn switch672
S68Outside mirror switch assy
S68.1Outside mirror adjustment switch638 to 640, 758 to 762
S68.3Left/right outside mirror switch637 to 641, 759 to 763
S68.4Parking position switch765
S82Washer fluid minimum capacity control switch736
S882 stage coolant temperature switch120, 121, 137, 138, 430, 431
S89Seat belt switch998
S93Coolant minimum capacity control switch737
S95Engine oil minuimum capacity control switch738
S98Headlamps levelling switch691 to 693
S99ZV driver door window lifter switch865
S100ZV passenger door window lifter switch883
S101Compressor switch926 to 928
S102Circulation switch918 to 920
S103Transmission temperature switch350
S104Kickdown switch493
S105Start-up assistance switch495 to 497
S106Economy power program switch492
S109Acceleration revolution pressure switch921
S115Coolant temperature switch487, 488
S116Stop lamp switch564, 565
S117Hydraulic pressure switch346
S120Engine compartment hood (anti-theft warning unit) switch835
S127Calibra tail gate central locking switch831
S128Coolant temperature switch936,937S131Defroster lever limit switch918
U2Computer851 to 862
U4ABS hydroaggregate1102 to 1122, 1146 to 1164
U4.1Pump motor relay1102, 1103, 1146, 1147
U4.2Solenoid valves relay1104, 1105, 1148, 1149
U4.3Pump motor1102,1146
U4.4Diode1105,1149
U4.5Left front solenoid valve1109,1153
U4.6Right front solenoid valve1111,1155
U4.7Rear axle solenoid valve1113,1157
U4.8ABS control unit1106 to 1122, 1150 to 1164
U4.9Solenoid valves plug1109 to 1113, 1153 to 1157
U5Check control display
U5.1Washer fluid minimum capacity telltale741
U5.2Oil minimum capacity telltale740
U5.3Coolant minimum capacity telltale739
U5.4Tail light & low beam telltale738
U5.5Stop light failure telltale737
U5.6Front brake lining telltale736
U12Filter heater
U12.1Temperature switch426, 452
U12.2Filter heater427, 453
U13Automatic transmission
U13.1Solenoid valve (shift 1)481
U13.2Solenoid valve (shift 2)482
U13.3Solenoid valve (lock up control)483
U13.4Solenoid valve (pressure control)484
U17Roof antenna amplifier795
V1Brake fluid test bulb diode712
V8Air conditioning compressor diode926
X1 onWiring connectorsVarious
X10Anti theft warning unit code837
X13Diagnostic link164, 165, 189, 190, 226, 270, 271, 258, 259,
309, 310, 370, 371, 343, 344, 473, 474, 573, 725, 836, 837, 860,
861, 1012, 1013, 1069, 1070, 1118, 1119, 1136, 1162, 1163
X15Octane number plug157, 158, 182, 183, 225, 226,
257, 258, 284, 285
X54Ignition coding plug310, 311, 1014, 1070, 1071
Y1Air conditioning compressor clutch925
Y4Headlamps washer solenoid valve620
Y5Fuel solenoid valve410, 445
Y7Fuel injection valves287 to 294,320 to 327,
384 to 391,1025 to 1032,1078 to 1089
Y10Hall sensor ignition distributor153 to 158
Y11Hot start solenoid valve375, 376
Y12Charging pressure control changeover valve377, 378
Y18Exhaust gas recirculation valve1093
Y23Inductive sensor distributor201 to 208
Y24Distributor (inductive discharge)
Y25Acceleration revolution solenoid valve155, 177
Y30Cold start acceleration solenoid valve 448
Y32Fuel injection valve212, 245
Y33Ignition distributor175 to 177, 268 to 270, 238 to 240,
301 to 303, 360 to 362
Y34Tank ventilation valve293, 331, 332, 379, 380,
1092, 1016, 1017,
Y35Circulation solenoid valve918
Y44Four wheel drive solenoid valve350
Y47Park brake shift lock lifting magnet469

16If adjustment is necessary, slacken the
locknut, turn the fork to give the specified
dimension, then tighten the locknut.
17Where applicable, coat the contact faces
of the servo and the mounting bracket with
sealing compound, then refit the bracket to
the servo, and tighten the securing nuts to the
specified torque.
18Coat the threads of the servo securing
bolts with locking fluid, then fit the servo to
the bulkhead and tighten the securing bolts.
19Refit the securing bolt cover plugs to the
cowl panel.
20Refit the master cylinder to the servo, and
tighten the securing nuts to the specified
torque.
21Reconnect the vacuum pipe to the servo.
22Refit the coolant expansion tank, as
described in Chapter 3.
23Refit the windscreen wiper motor and
linkage as described in Chapter 12, then refit
the windscreen cowl panel.
24Further refitting is a reversal of removal.
On completion, test the operation of the
servo, as described in Section 18.
20ABS hydraulic modulator -
removal and refitting
4
Note: Refer to Section 2, and the note at the
beginning of Section 3, before proceeding
Removal
1Disconnect the battery negative lead.
2Remove the brake fluid reservoir cap, and
secure a piece of polythene over the filler
neck with a rubber band, or by refitting the
cap. This will reduce the loss of fluid during
the following procedure.
3Remove the securing screw, and withdraw
the plastic cover from the hydraulic
modulator.
4Remove the two clamp screws, and lift off
the modulator wiring harness clamp (see
illustration).
5Disconnect the modulator wiring plug,
levering it from the socket with a screwdriver if
necessary.6Unscrew the brake fluid pipe union nuts,
and disconnect the pipes from the modulator.
Be prepared for fluid spillage, and plug the
open ends to prevent dirt ingress and further
fluid loss. Move the pipes just clear of the
modulator, taking care not to strain them.
7Unscrew the three modulator securing nuts
(see illustration), then tilt the modulator
slightly, and withdraw it upwards from its
bracket, sufficiently to gain access to the
earth lead securing nut at the front lower edge
of the modulator.
8Unscrew the securing nut and disconnect
the earth lead, then withdraw the modulator
from the vehicle, taking care not to spill brake
fluid on the vehicle paintwork.
9If a new modulator is to be fitted, pull the
two relays from the top of the old modulator,
and transfer them to the new unit. No attempt
must be made to dismantle the modulator.
Refitting
10Before refitting the modulator, check that
the bolts securing the mounting bracket to the
body panel are tight, and that the modulator
rubber mountings are in good condition.
Renew the rubber mountings if necessary.
11Refitting is a reversal of removal,
remembering the following points.
12Make sure that the earth lead is
reconnected before fitting the modulator to its
mounting bracket.13On completion, remove the polythene
sheet from the brake fluid reservoir filler neck,
and bleed the complete brake hydraulic
system, as described in Section 3.
14Check that the ABS warning lamp
extinguishes when first starting the engine
after the modulator has been removed. At the
earliest opportunity, take the vehicle to a
Vauxhall dealer, and have the complete
system tested, using the dedicated ABS test
equipment.
21ABS wheel sensors - removal
and refitting
3
Note: Refer to Section 2 before proceeding
Front wheel sensor
Removal
1Disconnect the battery negative lead.
2Where applicable, remove the wheel trim,
then loosen the relevant front roadwheel bolts
and apply the handbrake. Jack up the front of
the vehicle, and support on axle stands (see
“Jacking and Vehicle Support”) positioned
under the body side members. Remove the
roadwheel.
3Unclip the sensor wiring connector from the
retaining clip under the wheel arch, then
separate the two halves of the wiring
connector, prising them apart with a
screwdriver if necessary (see illustration).
4Using a Allen key or hexagon bit, unscrew
the bolt securing the wheel sensor to its
mounting bracket, then carefully lever the
sensor from the bracket using a screwdriver
(see illustration). Recover the seal ring.
Refitting
5Examine the condition of the seal ring, and
renew if necessary.
6Refitting is a reversal of removal,
remembering the following points.
7Smear a little grease on the sensor casing
before fitting it to the bracket.
8Do not fully tighten the roadwheel bolts until
the vehicle is resting on its wheels.
9Check that the ABS warning lamp
extinguishes when first starting the engine
after a wheel sensor has been removed. At
9•16Braking system
20.4 ABS hydraulic modulator (cover
removed)
1 Wiring harness
clamp screws2 Earth lead
3 Relays
21.3 Front wheel sensor wiring under
wheelarch - DOHC model
1 ABS sensor connector
2 Disc pad wear sensor wiring connector
21.4 ABS front wheel sensor securing bolt
(arrowed) - DOHC model20.7 ABS hydraulic modulator securing
screws (arrowed)

test (refer to Chapter 2A) will provide valuable
information regarding the overall performance
of the main internal components. Such a test
can be used as a basis to decide on the
extent of the work to be carried out. If, for
example, a compression test indicates serious
internal engine wear, conventional
maintenance as described in this Chapter will
not greatly improve the performance of the
engine. It may also prove a waste of time and
money, unless extensive overhaul work is
carried out first.
The following series of operations are those
most often required to improve the
performance of a generally poor-running
engine:Primary operations
a)Clean, inspect and test the battery (See
“Weekly Checks”)
b)Check all the engine related fluids (See
“Weekly Checks”)
c)Check the condition and tension of the
auxiliary drivebelt (Sections 18 and 22, as
appropriate).
d)Renew the spark plugs (Sections 30 and
37, as appropriate).
e)Inspect the distributor cap, rotor arm and
HT leads, as applicable (Section 31).
f)Check the condition of the air filter, and
renew if necessary (Section 27).
g)Check the fuel filter (Section 29).
h)Check the condition of all hoses, and
check for fluid leaks (Section 4).i)Check the idle speed and mixture
settings, as applicable (Section 9).
5If the above operations do not prove fully
effective, carry out the following secondary
operations:
Secondary operations
All items listed under “Primary operations”,
plus the following:
a)Check the charging system (Chapter 5).
b)Check the ignition system (Chapter 5).
c)Check the fuel system (Chapters 4A and
4B).
d)Renew the distributor cap and rotor arm
(Section 31).
e)Renew the ignition HT leads (Section 31).
3Engine oil and filter - renewal
2
1Ideally, the oil should be drained with the
engine hot, just after the vehicle has been
driven.
2On DOHC models, remove the engine
undershield to expose the sump drain plug
and the oil filter.
3Place a container beneath the oil drain plug
at the rear of the sump.
4Remove the oil filler cap from the camshaft
cover, then using a socket or spanner,
unscrew the oil drain plug, and allow the oil to
drain (see illustration). Take care to avoid
scalding if the oil is hot.
5Allow ten to fifteen minutes for the oil to
drain completely, then move the container
and position it under the oil filter.6On 1.8 and 2.0 litre models, improved
access to the oil filter can be gained by
jacking up the front of the vehicle and
removing the right-hand roadwheel (see
illustration). Ensure that the handbrake is
applied, and that the vehicle is securely
supported on axle stands (see “Jacking and
Vehicle Support”). Note that further oil may
drain from the sump as the vehicle is raised.
7Using a strap wrench or a filter removal tool
if necessary, slacken the filter and unscrew it
from the mounting. Alternatively, if the filter is
very tight, a screwdriver can be driven
through the filter casing and used as a lever.
Discard the filter.
8Wipe the mating face on the filter mounting
with a lint-free rag, then smear the sealing ring
of the new filter with clean engine oil of the
specified grade.
9Screw the new filter into position and
tighten it by hand only, do not use any tools.
10Where applicable, refit the roadwheel and
lower the vehicle to the ground. Fully tighten
the roadwheel bolts with the vehicle resting on
its wheels.
11Examine the condition of the oil drain plug
sealing ring and renew if necessary, then refit
the drain plug and tighten it to the specified
torque. 12Refill the engine through the filler on the
camshaft cover, using the specified grade and
quantity of oil. Fill until the level reaches the
“MAX” mark on the dipstick, allowing time for
the oil to drain through the engine to the
sump.
13Refit the oil filler cap, then start the engine
and check for leaks. Note that the oil pressure
warning lamp may stay illuminated for a few
seconds when the engine is started as the oil
filter fills with oil.
14Stop the engine and recheck the oil level,
topping-up if necessary.
15On DOHC models, refit the engine
undershield.
16Dispose of the old engine oil safely; do not
pour it down a drain.
4Hose and fluid leak check
1
1Visually inspect the engine joint faces,
gaskets and seals for any signs of water or oil
leaks. Pay particular attention to the areas
around the camshaft cover, cylinder head, oil
filter and sump joint faces. Remember that,
over a period of time, some very slight
seepage from these areas is to be expected -
what you are really looking for is any
indication of a serious leak. Should a leak be
found, renew the offending gasket or oil seal
by referring to the appropriate Chapters in this
manual.
Every 9000 miles or 12 months 1•9
3.6 Oil filter viewed through right-hand
wheel arch - SOHC model3.4 Sump drain plug location -
2.0 litre DOHC model
(engine undershield removed)
1
Basic service, every 9000 miles (15 000 km) or 12 months
As the drain plug releases
from the threads, move it
away quickly so the stream
of oil, running out of the
sump, goes into the container not up
your sleeve (see illustration).
Note: It is
antisocial and
illegal to dump oil
down the drain.
To find the
location of your
local oil recycling
bank, call this
number free.

At the same time, check the general
condition of the CV joints themselves by first
holding the driveshaft and attempting to
rotate the wheel. Repeat this check by holding
the inner joint and attempting to rotate the
driveshaft. Any appreciable movement
indicates wear in the joints, wear in the
driveshaft splines, or a loose driveshaft
retaining nut.
7Automatic transmission fluid
level check
2
Note: The transmission fluid level can be
checked either when it is cold (only below
35ºC (100ºF) outside temperature) or when it is
fully warmed up to normal operating
temperature (after driving for a distance of
approximately 12 miles/20 km). Since the fluid
level must be checked with the engine
running, ensure that the vehicle is parked on
level ground with the handbrake firmly applied
before leaving the driver’s seat. Be careful to
keep loose clothing, long hair, etc., well clear
of hot or moving components when working
under the bonnet
Transmission cold
1Park the vehicle on level ground and apply
the handbrake firmly. With the engine running
at no more than idle speed and your foot
firmly on the brake pedal, move the selector
lever through all positions, ending in position
“P”. Allow the engine to idle for one minute,
then check the level within two minutes.
2With the engine still idling and position “P”
still selected, open the bonnet and withdraw
the transmission dipstick from the filler tube
located in the front of the transmission casing,
at the left-hand end of the engine.
3Note the fluid’s condition (see below), then
wipe clean the dipstick using a clean,
non-fluffy rag, insert it fully back into the tube
and withdraw it again.
4The level should be up to the “MAX” mark
on the “+20°C” side of the dipstick (see
illustration).
5If topping-up is required, switch off the
ignition and add only good quality fluid of the
specified type through the filler tube. Ifsignificant amounts of fluid are being lost
(carefully note the amounts being added, and
how often), check the transmission for leaks
and either repair the fault or take the vehicle to
a Vauxhall dealer for attention.
6When the level is correct, ensure that the
dipstick is pressed firmly into the filler tube.
Transmission fully warmed up
7Work exactly as described above, but take
the level reading from the “+ 80°C” side of the
dipstick. In this case, the level must be
between the dipstick “MAX” and “MIN”
marks.
Checking the fluid’s condition
8Whenever the fluid level is checked,
examine the condition of the fluid and
compare its colour, smell and texture with that
of new fluid.
9If the fluid is dark, almost black, and smells
burnt, it is possible that the transmission
friction material is worn or disintegrating. The
vehicle should be taken to a Vauxhall dealer
or automatic transmission specialist for
immediate attention.
10If the fluid is milky, this is due to the
presence of emulsified droplets of water. This
may be caused either by condensation after a
prolonged period of short journeys or by the
entry of water through the dipstick/filler tube
or breather. If the fluid does not revert to its
normal appearance after a long journey it
must be renewed or advice should be sought
from a Vauxhall dealer or automatic
transmission specialist.
11If the fluid is varnish-like (i.e. light to dark
brown and tacky) it has oxidised due to
overheating or to over or under filling. If
renewal of the fluid does not cure the
problem, the vehicle should be taken to a
Vauxhall dealer or automatic transmission
specialist for immediate attention.
12If at any time on checking the fluid level or
on draining the fluid, particles of dirt, metal
chips or other foreign matter are found in the
fluid, the vehicle must be taken to a Vauxhall
dealer or automatic transmission specialist for
immediate attention. It may be necessary to
strip, clean and reassemble at least the valve
body, if not the complete transmission, to
rectify any fault.
8Radiator inspection and
cleaning
1
1Inspect radiator for leaks or corrosion,
especially around the outlet or inlet
connectors.
2Clean the radiator with a soft brush or
compressed air. Remove any debris, like dead
insects or leaves.
3If leaks are visible, replace radiator. Refer to
Chapter 3, if necessary.
9Idle speed and mixture -
adjustment
2
Note: On certain models, the idle and mixture
are automatically adjusted by a control unit,
therefore cannot be altered.
Refer to Chapters 4A or 4B as applicable.
10Throttle linkage
maintenance
2
On models built before 1992, lubricate the
throttle linkage, as described in Chapters 4A
or 4B, as applicable.
11Exhaust system check
2
1With the engine off, check the security of
the exhaust system. Pay particular attention
to the rubber mountings that suspend the
exhaust.
2Start the engine and check underneath for
leaks, which can be heard. This job is made
easier if you have access to a ramp.
3Listen for exhaust leaks from around the
front pipe to exhaust manifold joint.
4For further information, refer to Chapter 4C
12Wiring check
1
1Check all wiring in both the engine
compartment and under the car.
2Ensure that all wiring clips/clamps are secure.
3Pay particular attention to wiring near
components that get hot, i.e. exhaust
systems.
4Make sure that electrical connections are
secure and undamaged.
13Ignition timing
3
Refer to Chapter 5 for details.
Every 9000 miles or 12 months 1•11
7.4 When checking the fluid level, ensure
side of dipstick used corresponds with
fluid temperature
1
Warning: Voltages produced by
an electronic ignition system
are considerably higher than
those produced by conventional
ignition systems. Extreme care must be
taken when working on the system with
the ignition switched on. Persons with
surgically implanted cardiac pacemaker
devices should keep away from the
ignition circuits, components and test
equipment.

tighten the mounting nuts and bolts. On no
account lever at the free end of the alternator,
as serious internal damage could be caused.
3For details of replacement, see Chapter 5.
23Headlamp alignment
2
Refer to Chapter 12 for details.
24Door lock key battery -
replacement
1
1Carefully prise open the outer cover from
the key. Take care not to lose any of the
internal components, as they are loose.
2Remove the battery and discard it safely.
3Place the new battery, “+” side up (see
illustration). Check the operation of the key. If
the bulb does not light obtain a replacement.
4Replace the outer cover.
25Road 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 vehicle, 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, or when driving over bumps.
Drivetrain
6Check the performance of the engine,
clutch, transmission and driveshafts.
7Turn the radio/cassette off and listen for
any unusual noises from the engine, clutch
and transmission.
8Make sure that the engine runs smoothly
when idling, and that there is no hesitation
when accelerating.
9Check that the clutch action is smooth and
progressive, that the drive is taken up
smoothly, and that the pedal travel is not
excessive. Also listen for any noises when the
clutch pedal is depressed.
10Check that all gears can be engaged
smoothly, without noise, and that the gear
lever action is not abnormally vague or
“notchy”.
11Listen for a metallic clicking sound from
the front of the vehicle, as the vehicle is driven
slowly in a circle with the steering on full lock.
Carry out this check in both directions. If a
clicking noise is heard, this indicates wear in a
driveshaft joint, in which case, the complete
driveshaft must be renewed (see Chapter 8).
26Coolant renewal
2
Refer to Chapter 3 for details.
27Air cleaner element - renewal
2
Early round type
1Release the spring clips from the perimeter
of the air cleaner cover.
2Unscrew and remove the small cross-head
screw securing the cover extension to the
main body near the inlet duct.3Unscrew and remove the three central
cross-head cap nuts securing the air cleaner
to the carburettor, taking care not to drop the
washers and seals (see illustration).
4Separate the cover from the main body,
then lift out the element (see illustration).
5Wipe clean the inside surfaces of the cover
and main body.
6Locate the new element in the air cleaner
body, and refit the cover using a reversal of
the removal procedure.
Square type with air box
7If desired, to improve access, unclip the
coolant expansion tank hose from the air
cleaner cover.
8Release the two clips from the left-hand
side of the cover, and unscrew the two
screws from the right-hand side, then lift the
cover sufficiently to remove the element.
9Wipe clean the inside surfaces of the cover
and main body.
10Refitting is a reversal of removal, noting
that the element fits with the rubber locating
flange uppermost.
Every 18 000 miles or 24 months 1•13
24.3 Replacing the battery in the door lock
key
1 Battery (note, positive ‘+’ side up)
2 Bulb
27.4 Removing the air cleaner element -
note clip for crankcase ventilation hose
(arrowed)
27.3 Air cleaner-to-carburettor mounting
cap nuts
1
Full service, every 18 000 miles (30 000 km) or 24 months
Warning: Wait until the engine is
cold before starting the
procedure. Do not allow
antifreeze to come in contact
with your skin or with painted surfaces of
the vehicle. Rinse off spills with plenty of
water. Never leave antifreeze lying around
in an open container. Always clean spilt
fluids, as it can be harmful if swallowed.

28Air inlet temperature control
check (carburettor models
only)
2
Refer to Chapter 4A for details.
29Fuel filter renewal
3
Fuel filters are fitted in various locations
throughout the range. Some may be ‘in-line’ in
the fuel tank itself, or fitted into the
carburettor.
Refer to Chapters 4A or 4B, as appropriate.
30Spark plug renewal (SOHC)
2
1The correct functioning of the spark plugs is
vital for the correct running and efficiency of
the engine. It is essential that the plugs fitted
are appropriate for the engine. Refer to the
specifications in Chapter 5. If this type is used
and the engine is in good condition, the spark
plugs should not need attention between
scheduled service replacement intervals.
Spark plug cleaning is rarely necessary and
should not be attempted unless specialised
equipment is available, as damage can easily
be caused to the firing ends.
2Identify each HT lead for position so that the
leads can be refitted to their correct cylinders.
Then disconnect the leads from the plugs by
pulling on the connectors, not the leads.
3Clean the area around each spark plug
using a small paintbrush, then using a plugspanner (preferably with a rubber insert),
unscrew and remove the plugs (see
illustration). Cover the spark plug holes with
a clean rag to prevent the ingress of any
foreign matter.
4The condition of the spark plugs will tell
much about the overall condition of the
engine.
5If the insulator nose of the spark plug is
clean and white, with no deposits, this is a
sign of a weak mixture, or too hot a plug (a hot
plug transfers heat away from the electrode
slowly -a cold plug transfers heat away
quickly).
6If the tip and insulator nose is covered with
hard black-looking deposits, then this is
indicative that the mixture is too rich. Should
the plug be black and oily, then it is likely that
the engine is fairly worn, as well as the mixture
being too rich.
7If the insulator nose is covered with light tan
to greyish brown deposits, then the mixture is
correct, and it is likely that the engine is in
good condition.
8The spark plug gap is of considerable
importance, because if it is either too large or
too small, the size of the spark and its
efficiency will be seriously impaired. The spark
plug gap should be set to the figure given in
the Specifications, in Chapter 5.
9To set it, measure the gap with a feeler
blade and then bend open, or close, the outer
plug electrode until the correct gap is
achieved. The centre electrode should never
be bent, as this may crack the insulation and
cause plug failure, if nothing worse (see
illustrations).10Before fitting new spark plugs check that
their threaded connector sleeves are tight.
11Screw in the plugs by hand, then tighten
them to the specified torque. Do not exceed
the torque figure.
12Push the HT leads firmly onto the spark
plugs, ensuring that they are connected to
their correct cylinders.
31Distributor cap and HT lead
check
3
1Remove the distributor cap and HT leads,
and wipe them clean.
2Also wipe clean the coil connections.
Remove the rotor arm, then visually check the
distributor cap, rotor arm and HT leads for
hairline cracks, and signs of arcing.
1•14Every 18 000 miles or 24 months
30.9A Tools required for spark plug
removal, gap adjustment and refitting30.9C Measuring the spark plug gap with
feeler blade30.9B Measuring the spark plug gap with
wire gauge
30.3 Removing a spark plugWarning: Before carrying out
the following operation, refer to
the precautions given in “Safety
first!” at the beginning of this
manual, and follow them implicitly. Petrol
is a highly dangerous and volatile liquid,
and the precautions necessary when
handling it cannot be overstressed.
It is very often difficult to insert spark
plugs into their holes without cross-
threading them. To avoid this, fit a
short length of 8 mm (internal
diameter), rubber hose over the end of
the spark plug. The flexible hose acts
as a universal joint to help align the
plug correctly. Should the plug begin to
cross-thread, the hose will slip on the
spark plug, preventing damage to the
thread in the cylinder head.
Number the HT leads before
removal to ensure correct
refitting.

29Recover the cylinder head gasket and
discard it.
30Clean the cylinder head and block mating
faces by careful scraping. Take care not to
damage the cylinder head, which is made of
light alloy and is easily scored. Cover the
coolant passages and other openings with
masking tape or rag, to prevent dirt and
carbon falling in. Mop out all the oil from the
bolt holes; if oil is left in the holes, hydraulic
pressure could crack the block when the bolts
are refitted.
31If desired, the cylinder head can be
dismantled and inspected as described in
Section 10.
Refitting
32Begin refitting by locating a new gasket
on the block so that the word “OBEN” or
“TOP” is uppermost at the timing belt end of
the engine.
33With the mating faces scrupulously clean,
locate the cylinder head on the block so that
the positioning dowels engage in their holes.
34Temporarily refit the crankshaft pulley and
the camshaft sprockets, and ensure that the
timing marks are still positioned as they were
before the timing belt was removed (see
Section 4).35Fit the new cylinder head bolts, ensuring
that the washers are in place under their
heads, and screw the bolts in by hand as far
as possible.
36Tighten the bolts in the order shown (see
illustrations). Note that the tightening
sequence on X20 XEV differs to other DOHC
engines. Tighten the bolts in the four stages
given in the Specification (see Chapter 2A, as
2.0 litre) - i.e. tighten all bolts to the Stage 1
torque, then tighten all bolts to Stage 2 and so
on (see illustrations).
37Further refitting is a reversal of the
removal procedure, remembering the
following points.
38Refit the timing belt tensioner and idler
pulleys, camshaft sprockets and a new timing
belt as described in Section 4, and tension the
timing belt as described in Sections 4 and 5.
39Where applicable, refit the inlet manifold
to the cylinder head with reference to Chapter
4B, using a new gasket.
40Refit the front section of the exhaust
system as described in Chapter 4C, using a
new gasket.
41Refit the upper alternator mounting to the
inlet manifold (where applicable), then adjust
the alternator drivebelt tension, as described
in Chapter 5.
42Refill the cooling system, (Chapter 3).43On completion, check that all relevant
hoses, pipes and wires, etc., have been
reconnected.
44When the engine is started, check for
signs of leaks.
45Once the engine has reached normal
operating temperature, check and if
necessary adjust the mixture (where
applicable) with reference to Chapter 4B.
9Cylinder head -removal and
refitting (engine removed)
4
Note: New cylinder head bolts, a new cylinder
head gasket, and a new timing belt must be
used on refitting.
The torque settings (as shown in Chapter 2A)
are only applicable to latest specification head
bolts, available from Vauxhall. Earlier type or
alternative make, head bolts may require
different torques. Consult your supplier.
Removal
1The cylinder head can be removed
complete with the inlet manifold, or the inlet
manifold can be detached from the cylinder
head before removal, with reference to
Chapter 4B.
2Proceed as described in Section 8,
paragraphs 17 to 19 inclusive.
3If not already done, remove the distributor
cap and HT leads, referring to Chapter 5.
2B•8DOHC engine procedures
8.36A Cylinder head bolt tightening sequence -
20 XEJ and C 20 XE engines
8.36C Tighten the cylinder head bolts to
the specified torque . . .8.36D . . .and then through the specified
angle
8.36B Cylinder head bolt tightening sequence -
X 20 XEV engines
Warning: The exhaust valves
fitted to 20 XEJ and C 20 XE
models are fitted with sodium to
improve their heat transfer.
Sodium is a highly reactive metal, which
will ignite or explode spontaneously on
contact with water (including water vapour
in the air). These must NOT be disposed of
with ordinary scrap. Seek advice from a
Vauxhall dealer or your Local Authority, if
the valves are to be disposed.

23Cylinder head - inspection
and renovation
4
Note: Refer to a dealer for advice before
attempting to carry out valve grinding or valve
seat reciting operations, as these operations
may not be possible for the DIY mechanic.
This is due to the fitment of hardened valve
seats for use with unleaded petrol
Inspection
1Remember that the cylinder head is of light
alloy construction and is easily damaged, use
a blunt scraper or rotary wire brush to clean all
traces of carbon deposits from the
combustion spaces and the ports. The valve
stems and valve guides should also be freed
from any carbon deposits. Wash the
combustion spaces and ports down with
paraffin and scrape the cylinder head surface
free of any foreign matter with the side of a
steel rule, or a similar article.
2If the engine is installed in the car, clean the
pistons and the top of the cylinder bores. If
the pistons are still in the block, it is essential
that great care is taken to ensure that no
carbon gets into the cylinder bores. This could
scratch the cylinder walls or cause damage to
the pistons and rings. To ensure this does not
happen, first turn the crankshaft so that two of
the pistons are at the top of their bores. Insert
rag into the other two bores or seal them off
with paper and masking tape. The waterways
should also be covered with small pieces of
masking tape, to prevent particles of carbon
entering the cooling system and damaging the
coolant pump.
3Press a little grease into the gap between
the cylinder walls and the two pistons that are
to be worked on. With a blunt scraper,
carefully scrape away the carbon from the
piston crown, taking great care not to scratch
the aluminium. Also scrape away the carbon
from the surrounding lip of the cylinder wall.
When all carbon has been removed, scrape
away the grease that will now be
contaminated with carbon particles, taking
care not to press any into the bores. To assist
prevention of carbon build-up, the piston
crown can be polished with a metal polish.
Remove the rags or masking tape from the
other two cylinders, and turn the crankshaft
so that the two pistons that were at thebottom are now at the top. Place rag or
masking tape in the cylinders that have been
decarbonised, and continue as just described.
4Examine the heads of the valves for pitting
and burning, especially the heads of the
exhaust valves. The valve seatings should be
examined at the same time. If the pitting on
the valve and seat is very slight, the marks
can be removed by grinding the seats and
valves together with coarse, and then fine,
valve grinding paste.
5Where bad pitting has occurred to the valve
seats, it will be necessary to recut them and fit
new valves. This latter job should be entrusted
to the local dealer or engineering works. In
practice it is very seldom that the seats are so
badly worn. Normally it is the valve that is too
badly worn for refitting, and the owner can
easily buy a new set of valves and match
them to the seats by valve grinding.
Renovation
6Valve grinding is carried out as follows.
Smear a trace of coarse carborundum paste
on the seat face and apply a suction grinder
tool to the valve head. With a semi-rotary
motion, grind the valve head to its seat, lifting
the valve occasionally to redistribute the
grinding paste. When a dull matt even surface
is produced on both the valve seat and the
valve, wipe off the paste and repeat the
process with fine carborundum paste, lifting
and turning the valve to redistribute the paste
as before. A light spring placed under the
valve head will greatly ease this operation.
When a smooth unbroken ring of light grey
matt finish is produced, on both valve and
valve seat faces, the grinding operation is
complete. Carefully clean away every trace of
grinding compound, taking great care to leave
none in the ports or in the valve guides. Clean
the valves and valve seats with a
paraffin-soaked rag, then with a clean rag,
and finally, if an air line is available, blow the
valves, valve guides and valve ports clean.
7Check that all valve springs are intact. If any
one is broken, all should be renewed. Check
the free height of the springs against new
ones. If some springs are not long enough,
replace them all. Springs suffer from fatigue
and it is a good idea to renew them even if
they look serviceable. 8The cylinder head can be checked for
warping either by placing it on a piece of plate
glass or using a straight-edge and feeler
blades. If there is any doubt or if its block face
is corroded, have it re-faced by your dealer or
motor engineering works.
9On 1.8 and 2.0 litre, always renew the
sealing ring between the cylinder head and
the thermostat housing when the head is
removed for overhaul (see illustration).
Reference to Chapter 21 will show that a
considerable amount of work is involved if it is
wished to renew the sealing ring with the
cylinder head installed.
10If the oil pressure regulating valve in the
cylinder head is to be renewed, access is
gained through the circular plug covering the
end of the valve (see illustration). The old
valve must be crushed, then its remains
extracted, and a thread (M10) cut in the valve
seat to allow removal using a bolt. A new
valve and plug can then be driven into
position. In view of the intricacies of this
operation, it is probably best to have the valve
renewed by a Vauxhall dealer if necessary.
24Hydraulic valve lifters -
inspection
4
Inspection
1On engines that have covered a high
mileage, or for which the service history
(particularly oil changes) is suspect, it is
possible for the valve lifters to suffer internal
contamination. In extreme cases this may
result in increased engine top end noise and
wear. To minimise the possibility of problems
occurring later in the life of the engine, it is
advisable to dismantle and clean the hydraulic
valve lifters as follows whenever the cylinder
head is overhauled. Note that no spare parts
are available for the valve lifters, and if any of
the components are unserviceable, the
complete assembly must be renewed (see
illustration).
2With the cylinder head removed and
dismantled as described in Sections 21 and
23, first inspect the valve lifter bores in the
2A•24SOHC engine procedures
23.10 Oil pressure regulating valve (1) and
plug (2) - 2.0 litre engine23.9 Renewing the thermostat housing
sealing ring - 2.0 litre engine
Warning: The exhaust valves
fitted to 20 XEJ and C 20 XE
(DOHC) models are fitted with
sodium to improve their heat
transfer. Sodium is a highly reactive
metal, which will ignite or explode
spontaneously on contact with water
(including water vapour in the air). These
must NOT be disposed of with ordinary
scrap. Seek advice from a Vauxhall dealer
or your Local Authority, if the valves are to
be disposed of.