1988 OPEL CALIBRA engine coolant

1•4Maintenance schedule
Every 250 miles (400 km) or weekly
MRefer to “Weekly checks”
Basic service, every 9000 miles
(15 000 km) or 12 months -
whichever comes sooner
Along with the items in “Weekly checks”, carry out the
following:
MRenew the engine oil and oil filter (Section 3).
MCheck all hoses and other components for fluid
leaks (Section 4).
MCheck the steering and suspension components
(Section 5).
MCheck the condition of the driveshaft rubber
gaiters (Section 6).
MCheck the automatic transmission fluid level (if
applicable), (Section 7).
MCheck the radiator for blockage (e.g. dead insects)
and clean as necessary (Section 8).
MCheck and adjust the idle speed and mixture (if
applicable), (Section 9).
MCheck the throttle linkage and lubricate if
necessary (Section 10).
MCheck the exhaust system for corrosion, leaks and
security (Section 11).
MCheck all wiring for condition and security
(Section 12).
MCheck and adjust the ignition timing (if applicable),
(Section 13).
MRenew the brake fluid (Section 14).
MCheck the brake pad friction material for wear
(Section 15).
MCheck the handbrake linkage (Section 16).
MCheck the power steering fluid level (if applicable),
(Section 17).
MCheck the power steering pump drivebelt (if
applicable), (Section 18).
MCheck the rear suspension level control system
height, if fitted (Section 19).
MCheck the bodywork (Section 20).
MLubricate all locks and hinges (Section 21).
MCheck the alternator V-belt (Section 22).
MCheck the headlamp alignment (Section 23).
MReplace battery in the door-lock key (if applicable),
(Section 24).
MCarry out a road test (Section 25).
Note: Vauxhall specify that an Exhaust Emissions Test should be
carried out at least annually. However, this requires special
equipment, and is performed as part of the MOT test (refer to the
end of the manual).
Full service, every 18 000 miles
(30 000 km) or 24 months -
whichever comes sooner
Along with the ‘basic service’, carry out the following:
MRenew the coolant (Section 26).
MRenew the air cleaner element (Section 27).
MCheck the operation of the air cleaner air inlet
temperature control (carburettor models only),
(Section 28).
MRenew the fuel filter (Section 29).
MRenew the spark plugs (SOHC only), (Section 30) *.
MInspect and clean the distributor cap and HT leads
(Section 31).
MCheck the clutch cable adjustment (Section 32).
MCheck the manual transmission oil level (Section 33).
MCheck the automatic transmission (Section 34).
MCheck the brake drum shoe for wear (Section 35).
Major service, every 36 000 miles
(60 000 km) or 48 months -
whichever comes sooner
Along with the ‘full service’, carry out the following:
MRenew timing belt (Section 36).
MRenew the spark plugs (DOHC models only),
(Section 37).
MRenew automatic transmission fluid (Section 38) *.
* Note: If a vehicle is used for heavy-duty work (e.g. taxi work,
caravan/trailer towing, mostly short-distance, stop-start city driving)
the fluid must be changed every 36 months or 27 000 miles (45 000
km), whichever occurs first.

Maintenance - component location 1•5
1
Underbonnet view of a 1989 1.6 L model (16 SV engine)
1 VIN plate
2 Air cleaner casing *
3 Suspension strut top
4 Coolant expansion tank
5 Brake fluid reservoir
6 Fuel pump
7 Steering rack
8 Octane rating plug
9 Washer fluid reservoir
10 Battery
11 Ignition coil
12 Distributor (Bosch type)
13 Cooling fan motor
14 Engine oil level dipstick
15 Oil filter
16 Oil filler cap
* Refer to Chapter 4A for
alternative type
Underbonnet view of a 1991 model Cavalier 1.6 L (C16 NZ engine)
1 Air cleaner casing
2 Suspension strut top
3 Coolant expansion tank
4 Brake fluid reservoir
5 Air box
6 Exhaust gas recirculation valve
7 Steering gear
8 Octane coding plug
9 Washer fluid reservoir
10 Battery
11 Ignition coil
12 Distributor
13 Cooling fan motor
14 Engine oil level dipstick
15 Engine oil filter
16 Oxygen sensor
17 Engine oil filler cap

1•6Maintenance - component location
Underbonnet view of a 1989 2.0 SRi model (20 SEH engine)
1 VIN plate
2 Air cleaner casing
3 Airflow meter
4 Suspension strut top
5 Coolant expansion tank
6 Brake fluid reservoir
7 Throttle body
8 Relay box
9 Octane rating plug
10 Washer fluid reservoir
11 Battery
12 Power steering fluid reservoir
13 Power steering fluid hoses
14 Distributor cap
15 Engine oil level dipstick
16 Idle speed adjuster
17 Fuel pressure regulator
18 Oil filler cap
19 Thermostat housing
Underbonnet view of a 1990 GSi 2000 model (20 XEJ engine)
1 VIN plate
2 Air cleaner casing
3 Suspension strut top
4 Coolant expansion tank
5 Brake fluid reservoir
6 Air mass meter
7 Fuel pressure regulator
8 Relay box
9 Anti-theft alarm horn
10 ABS hydraulic modulator
11 Washer fluid reservoir
12 Power steering fluid reservoir
13 Battery
14 Distributor
15 Engine oil level dipstick
16 Oil filler cap

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.

Valves and guidesInletExhaust
Overall length - production (mm):
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105.0105.0
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102.092.0
Overall length - service (mm):
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104.6104.6
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101.791.8
Head diameter (mm):
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33.0 ±0.129.0 ±0.1
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32.0 ±0.129.0 ±0.1
Stem diameter (mm):
20 XEJ and C20 XE
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.955 to 6.9706.945 to 6.960
0.075 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.030 to 7.0457.020 to 7.035
0.150 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.105 to 7.1207.095 to 7.110
0.250 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.205 to 7.2207.195 to 7.210
X20 XEV
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.955 to 5.9705.945 to 5.960
0.075 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.030 to 6.0456.020 to 6.035
0.150 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.105 to 6.1206.095 to 6.110
Valve guide bore (mm):
20 XEJ and C20 XE
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.000 to 7.015
0.075 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.075 to 7.090
0.150 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.150 to 7.165
0.250 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.400 to 7.415
X20 XEV
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.000 to 6.012
0.075 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.075 to 6.090
0.150 mm oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.150 to 6.165
Valve seat angle (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44°40’
Lubrication system
Lubricant capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1 Specifications
Oil pressure at idle (engine warm):
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.5 bar
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 bar
Torque wrench settingsNmlbf ft
Note: Use new bolts (or nuts, if applicable), where asterisked (*).
Alternator to cylinder block bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . .3526
Brake servo line to inlet manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2015
Camshaft bearing cap to cylinder head (M6) . . . . . . . . . . . . . . . . . . . . .107
Camshaft bearing cap to cylinder head (M8) . . . . . . . . . . . . . . . . . . . . .2015
Camshaft bearing cap to head (X20 XEV) . . . . . . . . . . . . . . . . . . . . . . .86
Camshaft pulley to camshaft (1993-on models):
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5037
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle tighten by 60°
Stage 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle tighten by 15°
Coolant pipe to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2015
Cover to cylinder head (M6 bolts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
Cover to cylinder head (M8 nuts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2216
Cover to exhaust manifold (X20 XEV) . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Crankshaft pulse pick-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
Exhaust manifold to cylinder head * . . . . . . . . . . . . . . . . . . . . . . . . . . . .2216
Exhaust pipe to adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
Inlet manifold support to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . .2518
Intermediate shaft bracket to cylinder block . . . . . . . . . . . . . . . . . . . . .5541
Knock sensor to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2014
Oil cooler lines to adapter/oil cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . .3022
Oil filter to oil pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1511
Oil dipstick flange to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Oil pump safety valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3022
Oil pump, threaded adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2317
Power steering pump to support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Spark plug lead cover to cylinder head cover:
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
X 20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
2B•2DOHC engine procedures

Torque wrench settings (continued)Nmlbf ft
Starter to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4533
Starter support to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Temperature regulator plug (M20) * . . . . . . . . . . . . . . . . . . . . . . . . . . . .3022
Timing belt cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Timing belt drive gear to crankshaft: *
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .250184
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle tighten by between 40°and 50°
Timing belt guide roller bracket to block . . . . . . . . . . . . . . . . . . . . . . . .2518
Timing belt guide roller to bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Timing belt guide roller to cylinder block:
Engines up to 1993
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle tighten by 45°
Stage 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle tighten by 15°
1993-on engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Transfer box bracket to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . .6044
Transmission to cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6044
1General
This part of Chapter 2 describes
procedures that are specific to the DOHC
engine. It should be read in conjunction with
Part A.
The lower engine is basically the same as
the 2.0 litre SOHC. However the pistons are
attached to the connecting rods by gudgeon
pins, which are fully floating, and are secured
by circlips.
Both camshafts on these engines are driven
from the crankshaft by one toothed
composite rubber belt. Each cylinder has four
valves (two inlet and two exhaust), operated
directly from the camshafts by hydraulic
self-adjusting valve lifters. One camshaft
operates the inlet valves, and the other
operates the exhaust valves.
DOHC models are fitted with a remotely
mounted oil cooler.
The distributor is driven directly from the
exhaust camshaft.
2Engine - removal and refitting
4
Removal
1Carry out procedure in Chapter 2A, noting
the following differences.
2With the car safely raised, remove the
engine undershield.
3The fuel hoses need to be disconnected
from the fuel rail.
4Disconnect coolant hoses from the cylinder
block and cylinder head. Also disconnect the
oil cooler pipe unions from the oil pump.
5Unbolt the right-hand driveshaft centre
bearing support bracket from the rear of the
cylinder block.
Refitting
6Refitting the engine is similar to theprocedure in Chapter 2A. The exceptions
being, replacement of the right-hand
driveshaft centre bearing support bracket at
the rear of the cylinder block and retightening
the securing bolts.
7Replace the undershield.
3Engine/transmission
mountings- renewal
3
The procedure for replacing the engine/
transmission is similar to SOHC models, see
Chapter 2A. However this engine is fitted with
an undershield that needs to be removed
before replacing the mounts. Do not forget to
replace the undershield before lowering the
car.
4Timing belt, sprockets and belt
tensioner and idler pulleys-
removal, refitting and adjustment
3
Note: The timing belt should be renewed on
refitting. A two-legged puller may be required
to remove the crankshaft sprocket
Removal
1Disconnect the battery negative lead.2Disconnect the air cleaner trunking from the
airflow meter, then remove the cover and the
air cleaner element from the air cleaner. If
desired, for improved access, the complete
air cleaner assembly can be removed, as
described in Chapter 4B.
3Remove the power steering pump drivebelt,
as described in Chapter 10.
4Remove the alternator drivebelt, as
described in Chapter 5.
5Remove the three securing screws, and
withdraw the outer timing belt cover. Recover
the rubber grommets from the screw holes in
the cover if they are loose.
6Turn the crankshaft using a Torx socket on
the crankshaft sprocket bolt, until the timing
marks on the camshaft sprockets are aligned
with the notches in the camshaft cover. The
notch in the crankshaft pulley should also be
aligned with the pointer on the rear timing belt
cover (see illustrations).
7Extract the six securing bolts using a
splined bit, and withdraw the crankshaft
pulley (see illustration). If necessary,
counterhold the crankshaft using a socket on
the crankshaft sprocket bolt. If the engine is in
the vehicle, the crankshaft can be prevented
from turning by having an assistant engage
first gear and depress the brake pedal.
Alternatively, the flywheel ring gear teeth can
be jammed using a large screwdriver or
similar tool. Before removing the pulley, check
that the timing marks are still aligned.
DOHC engine procedures 2B•3
4.6B . . .and notch in crankshaft pulley
aligned with pointer on rear timing belt
cover (circled)4.6A Camshaft sprocket TDC mark
aligned with notch in camshaft cover
2B

48Turn the crankshaft clockwise until the
TDC marks on the camshaft sprockets are
aligned with the notches in the camshaft
cover, and check that the crankshaft pulley
TDC mark is aligned with the pointer on the
rear timing belt cover.
49Proceed as described in paragraphs 30 to
34 inclusive.
5Timing belt, with automatic
adjuster- removal, refitting
and adjustment
3
Removal
1The operations are essentially the same as
described in Section 4, except that the
tensioner pulley incorporates an automatic
adjuster that simplifies the procedure as
follows.
2To release the belt tension before removal,
unscrew the timing belt tensioner pulley
securing bolt slightly then, with a large
screwdriver (or similar tool) inserted in the slot
on the tensioner arm, turn the tensioner arm
until the timing belt is slack. Tighten the
securing bolt slightly to hold the tensioner in
this position.
Refitting
3To refit the timing belt, first ensure that the
coolant pump is correctly positioned by
checking that the lug on the coolant pump
flange is aligned with the corresponding lug
on the cylinder block. If this is not the case,
slacken the coolant pump mounting bolts
slightly and move the pump accordingly.
Tighten the bolts to the specified torque on
completion (see Chapter 3).
4Refit the timing belt as described in Section 4,
then tension it as follows.
Adjustment
5Slacken the tensioner pulley securing bolt
and move the tensioner arm anti-clockwise,
until the tensioner pointer lies at its stop.
Tighten the tensioner pulley securing bolt to
hold the tensioner in this position.
6Turn the crankshaft through two complete
revolutions in the normal direction of rotation
and check that with the crankshaft pulley TDC
mark aligned with the pointer on the rear
timing belt cover, the TDC marks on the
camshaft sprockets are still aligned with the
notches in the camshaft cover.
7Slacken the tensioner pulley securing bolt
once again and move the tensioner arm
clockwise, until the tensioner pointer is
aligned with the notch in the tensioner. In the
first few hours of operation a new belt will be
subjected to ‘settling-in’, (known as the
running-in procedure). If you are refitting a
used belt (one that has been ‘run-in’), align the
pointer to approximately 4 mm to the left of
the notch, refer to Section 14 in Chapter 2A.
Tighten the tensioner pulley securing bolt
securely. Turn the crankshaft through onecomplete revolution in the normal direction of
rotation and check that the crankshaft and
camshaft timing marks still align, then refit the
remainder of the components as described in
Section 4.
8With the timing belt adjustment set in this
way, correct tension will always be maintained
by the automatic tensioner and no further
checking or adjustment will be necessary.
6Camshaft front oil seal-
removal and refitting
3
Note: A new timing belt should be used on
refitting
Removal
1The camshaft front oil seals may be
renewed with the engine in the vehicle without
removing the camshafts as follows.
2Remove the timing belt and the relevant
camshaft sprocket(s), as described in Section 4.
3Punch or drill a small hole in the centre of
the now-exposed oil seal. Screw in a
self-tapping screw, and pull on the screw with
pliers to extract the seal.
4Clean the oil seal seat with a wooden or
plastic scraper.
5Turn the camshaft until the locating peg for
the camshaft sprocket is uppermost, then
lubricate the lips of a new camshaft front oil
seal with a little grease, and fit the oil seal,
using a tube or socket of similar diameter with
a washer and the camshaft sprocket bolt.Screw the camshaft sprocket bolt into the end
of the camshaft to draw the oil seal into
position on its shoulder (see illustration).
6Where applicable, repeat the procedure on
the remaining camshaft oil seal.
Refitting
7Refit the camshaft sprockets, the timing
belt and tension the timing belt as described
in Sections 4 and 5.
7Camshafts- removal,
inspection and refitting
4
Note: A new timing belt should be used on
refitting
Removal
1Remove the timing belt and the relevant
camshaft sprockets, as described in Section 4.
2If the exhaust camshaft is to be removed,
unscrew the two securing bolts and remove
the distributor from the end of the cylinder
head, referring to Chapter 5, if necessary.
3Check the camshaft bearing caps for identi-
fication marks, and if none are present, make
corresponding marks on the bearing caps and
the top surface of the cylinder head using a
centre punch. Note the orientation of the
bearing caps before removal, as they must be
refitted in exactly the same positions from
which they are removed (see illustration).
4Loosen the relevant camshaft bearing cap
nuts by half a turn, then loosen all the nuts by
a further half turn and so on (this is necessary
to slowly relieve the tension in the valve
springs). Note that the exhaust camshaft rear
bearing cap that also supports the distributor
is secured by four nuts (see illustration).
5Remove the bearing cap nuts and the
bearing caps, then carefully lift the relevant
camshaft from the cylinder head without
jerking.
6Repeat the procedure for the remaining
camshaft if desired.
Inspection
7With the camshaft(s) removed, examine the
bearing surfaces in the cylinder head and
bearing caps for signs of obvious wear or
2B•6DOHC engine procedures
6.5 Using the camshaft sprocket bolt,
washer, and a tube to fit a new camshaft
front oil seal
7.4 Exhaust camshaft rear bearing cap
securing nuts (arrowed)7.3 Camshaft bearing cap. Note position
of identification mark (arrowed)

pitting. If evident, the cylinder head and all
bearing caps must be renewed as a matched
set, as there is no provision for refacing if the
bearing caps cannot be renewed individually.
8The camshaft(s) should show no marks or
scoring on the journal or cam lobe surfaces. if
evident, renew the camshaft(s).
9It is advisable to renew the camshaft front
oil seal(s) as a matter of course. Prise the old
seal(s) from the front of the camshaft(s) and
discard them.
Refitting
10Begin refitting by liberally coating the
contact faces of the hydraulic valve lifters and
the camshaft(s) with molybdenum disulphide
paste.
11Coat the mating faces of the front and
rear bearing caps with sealing compound and
refit the bearing caps in their original positions
as noted during removal.
12Tighten the camshaft bearing cap nuts to
the specified torque in half-turn stages, as
when loosening the nuts. Note that when
refitting the exhaust camshaft, the two smaller
rear bearing cap securing nuts should be
tightened after all the main camshaft bearing
cap nuts have been tightened. Note also that
the two smaller nuts should be tightened to a
lower torque wrench setting than the main
nuts.
13Turn the camshaft until the locating peg
for the camshaft sprocket is uppermost, then
lubricate the lips of a rear camshaft front oil
seal with a little grease, and fit the oil seal,
using a tube or socket of similar diameter with
a washer and the camshaft sprocket bolt.
Screw the camshaft sprocket bolt into the end
of the camshaft to draw the oil seal into
position on its shoulder.
14Repeat the procedure for the remaining
camshaft.
15Refit the distributor with reference to
Chapter 5. Fit a new timing belt and the
camshaft sprockets, then adjust the timing
belt as described in Section 4 or 5, as
applicable.
8Cylinder head -removal and
refitting (engine in vehicle)
4
Note: The engine must be cold when the
cylinder head is removed. Do not remove the
cylinder head from a hot engine. 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
1Disconnect the battery negative lead.
2Drain the cooling system, as described in
Chapter 3.3Remove the front section of the exhaust
system, as described in Chapter 4C.
4The 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. If no work is to be carried out on
the inlet manifold, it can be unbolted from the
cylinder head and supported to one side out
of the way, thus avoiding the need to
disconnect the relevant hoses, pipes and
wiring.
5If the cylinder head is to be removed
complete with the inlet manifold, disconnect
all relevant hoses, pipes and wiring from the
inlet manifold and associated components,
referring to Chapter 4B, and unbolt the
manifold support bracket from the manifold.
Loosen the alternator mountings with
reference to Chapter 5, then unbolt the upper
alternator mounting from the inlet manifold.
6If the inlet manifold is to be left in the engine
compartment, continue as follows, otherwise
go on to paragraph 17.
7Disconnect the wiring plug from the airflow
meter, and the breather hose from the air box
on the throttle body. Disconnect the air
cleaner trunking and remove the airflow
meter/air box assembly from the throttle
body. Refer to Chapter 4B if necessary.
8Disconnect the end of the throttle cable
from the throttle valve lever, then unbolt the
throttle cable support bracket and remove it
from the inlet manifold.
9Unscrew the two earth lead securing nuts
from the fuel rail (one at each end of the rail)
and disconnect the three earth leads.
10Disconnect the wiring plug from the
throttle position switch.
11Pull up on the wiring harness housing, and
disconnect the wiring plugs from the fuel
injectors by compressing the retaining clips.
Move the wiring harness housing to one side.
12Disconnect the two breather hoses from
the rear of the camshaft cover.
13Loosen the alternator mountings, with
reference to Chapter 5, then unbolt the upper
alternator mounting from the inlet manifold.
14Unbolt the manifold support bracket from
the manifold.15Make a final check to ensure that all
necessary hoses, pipes and wires have been
disconnected, then unscrew the securing nuts
and lift the inlet manifold from the cylinder
head. Ensure that the manifold is properly
supported, taking care not to strain any of the
hoses, pipes and wires, etc., which are still
connected.
16Recover the manifold gasket from the
cylinder head.
17Remove the timing belt, camshaft
sprockets, and timing belt tensioner and idler
pulleys, as described in Section 4.
18Unscrew the upper and middle studs for
the timing belt outer cover screws. Note that
the upper stud simply unscrews from the
cylinder head, but the middle stud is secured
by a bolt.
19Unscrew the two upper rear timing belt
cover securing bolts from the cylinder head.
20Remove the distributor cap and HT leads
with reference to Chapter 5.
21Disconnect the distributor wiring plug.
22Disconnect the coolant hose from the
left-hand end of the cylinder head.
23Unscrew the bolt securing the crankcase
breather tube bracket to the end of the
cylinder head.
24Disconnect the radiator top hose from the
thermostat housing, and disconnect the
wiring plugs from the temperature gauge
sender and the coolant temperature sensor
(both situated in the thermostat housing).
25Make a final check to ensure that all
relevant hoses, pipes and wires have been
disconnected.
26On X20 XEV models, remove the
camshaft, as described in Section 7.
27Using a Torx socket, and working in the
order shown (see illustrations), loosen all the
cylinder head bolts by a quarter of a turn, then
loosen all the bolts by half a turn, and finally
loosen and remove the bolts. Recover the
washers. Note that the loosening sequence
on X20 XEV differs to other DOHC engines.
28Lift the cylinder head from the cylinder
block. If necessary, tap the cylinder head
gently with a soft-faced mallet to free it from
the block, but do not lever at the mating
faces. Note that the cylinder head is located
on dowels.
DOHC engine procedures 2B•7
8.27B Cylinder head bolt loosening
sequence - (X 20 XEV engines)8.27A Cylinder head bolt loosening
sequence - (20 XEJ and C 20 XE engines)
2B