1988 OPEL CALIBRA ECO mode

1Introduction
This Chapter is designed to help the home
mechanic maintain his/her vehicle for safety,
economy, long life and peak performance.
The Chapter contains a master maintenance
schedule, followed by Sections dealing specifically
with each task in the schedule. Visual checks,
adjustments, component renewal and other helpful
items are included. Refer to the accompanying
illustrations of the engine compartment and the
underside of the vehicle for the locations of the
various components.
Servicing your vehicle according to the
mileage/time maintenance schedule and the
following Sections will provide a planned
maintenance programme, which should result in a
long and reliable service life. This is a comprehensiveplan, so maintaining some items but not others at
the specified service intervals, will not produce the
same results.
As you service your vehicle, you will
discover that many of the procedures can -
and should - be grouped together, because of
the particular procedure being performed, or
because of the proximity of two otherwise-
unrelated components to one another. For
example, if the vehicle is raised for any
reason, the exhaust can be inspected at the
same time as the suspension and steering
components.
The first step in this maintenance
programme is to prepare yourself before the
actual work begins. Read through all the
Sections relevant to the work to be carried
out, then make a list and gather all the parts
and tools required. If a problem is found, seek
advice from a parts specialist, or a dealer
service department.
2Intensive maintenance
If, from the time the vehicle is new, routine
maintenance schedule is followed closely,
frequent checks made of fluid levels and high-
wear items, as recommended, the engine will
be kept in relatively good running condition.
The need for additional work will be minimised
It is possible that there will be times when
the engine is running poorly due to the lack of
regular maintenance. This is even more likely
if a used vehicle, which has not received
regular and frequent maintenance checks, is
purchased. In such cases, additional work
may need to be carried out, outside of the
regular maintenance intervals.
If engine wear is suspected, a compression
1•8Maintenance - component location
Rear underbody view of a 1990 GSi 2000 model (fully independent rear suspension)
1 Fuel tank securing strap
2 Shock absorber
3 ABS wheel sensor
4 Semi-trailing arm
5 Suspension crossmember
mounting bracing bracket
6 Handbrake cable
7 Suspension crossmember
8 Exhaust expansion box
9 Fuel pump
Maintenance procedures

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.

2B
Note:All specifications as for 2.0 litre SOHC engines, unless shown otherwise
General
Type (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Four-cylinder, in-line, water-cooled, transversely mounted. Double
belt-driven overhead camshafts, acting on hydraulic valve lifters
Manufacturer’s engine codes:
20 XEJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 litre (1998 cc)
C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 litre (1998 cc) + catalyst
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 litre (1998 cc) + catalyst. ‘Ecotec’ type engine
Compression ratio:
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5 : 1
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8 : 1
Maximum power:
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 kW (150 bhp) at 6000 rpm
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 kW (136 bhp) at 5400 rpm
Maximum torque:
20 XEJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Nm at 4800 rpm
C20 XE
Up to model year 1993 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Nm at 4800 rpm
1993-on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Nm at 4600 rpm
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 Nm at 4000 rpm
Cylinder Head
Overall height of cylinder head (sealing surface to sealing surface):
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.58 to 135.68 mm
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134.00 mm
Installation height of valve guide:
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.70 to 11.00 mm
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.70 to 14.00 mm
Camshaft
Camshaft bearing journal diameter (all models) . . . . . . . . . . . . . . . . . . . 27.939 to 27.960 mm
Camshaft bearing diameter in housing (all models) . . . . . . . . . . . . . . . . 28.000 to 28.021 mm
Cam lift:
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5 mm
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.0 mm
Maximum permissible radial run-out:
20 XEJ and C20 XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.04 mm
X20 XEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.06 mm
Endfloat (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.144 mm
Chapter 2 Part B:
DOHC engine procedures
Camshaft front oil seal - removal and refitting . . . . . . . . . . . . . . . . . . .6
Camshafts - removal, inspection and refitting . . . . . . . . . . . . . . . . . . .7
Crankshaft front oil seal - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Cylinder head - dismantling and reassembly . . . . . . . . . . . . . . . . . . .10
Cylinder head - removal and refitting (engine in vehicle) . . . . . . . . . . .8
Cylinder head - removal and refitting (engine removed) . . . . . . . . . . . .9
Engine - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Engine/transmission mountings - renewal . . . . . . . . . . . . . . . . . . . . . .3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1Oil cooler - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Oil pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Sump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Timing belt, sprockets and belt tensioner and idler pulleys - removal,
refitting and adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Timing belt, with automatic adjuster - removal, refitting and
adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Valve lifters - general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2B•1
Specifications Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321

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

Apply a little grease to the threads of the
securing bolt, and tighten it to the specified
torque in the two stages given in the Specifi-
cations. Ensure that the thrustwasher is in
place under the bolt head, and prevent the
crankshaft from turning as during removal.
23Refit the camshaft sprockets. Ensure that
the locating pins on the ends of the camshafts
engage with the holes in the sprockets and
with the sprocket timing marks facing
forwards. Then tighten the securing bolts to
the specified torque in the two stages given in
the Specifications. Prevent the camshafts
from turning as during removal.
24Check the condition of the camshaft
cover rubber gasket and renew if necessary,
then refit the camshaft cover and tighten the
securing bolts (see illustration).
25Refit the HT leads to the spark plugs
(ensuring that they are refitted to their correct
cylinders), then clip the leads to the end of the
camshaft cover. Refit the spark plug cover
and tighten the securing bolts.
26Reconnect the breather hose to the
camshaft cover.
27Temporarily refit the crankshaft pulley,
and ensure that the crankshaft pulley and
camshaft sprocket timing marks are still
aligned as described in paragraph 6. Then fit a
new timing belt around the sprockets and
pulleys, starting at the crankshaft sprocket.
28Refit the crankshaft pulley, and tighten the
securing bolts to the specified torque. If
necessary, prevent the crankshaft from
turning as during removal. 29Adjust the timing belt tension, as
described from paragraph 35 onwards.
30Refit the outer timing belt cover, ensuring
that the rubber grommets are in place in the
screw holes, and tighten the securing screws.
31Refit the alternator drivebelt and adjust
the drivebelt tension, as described in Chapter
5.
32Refit the power steering pump drivebelt
and adjust the drivebelt tension, as described
in Chapter 10.
33Refit the air cleaner components as
applicable, referring to Chapter 4B, if
necessary.
34Reconnect the battery negative lead.
Adjustment
Note: The manufacturers specify the use of
special adjustment wrench Vauxhall tool No
KM-666 for adjusting the timing belt tension. If
access to this tool cannot be obtained an
approximate adjustment can be achieved
using the method described in this Section.
However it is emphasised that the vehicle
should be taken to a dealer at the earliest
possible opportunity to have the tension
adjusted using the special tool. Do not drive
the vehicle over any long distance until the
belt tension has been adjusted by a dealer
Approximate adjustment
35No checking of timing belt adjustment is
specified, and the following adjustment
procedure applies to a newly fitted belt. The
adjustment must be carried out with the
engine cold.36With the timing belt cover removed and
the tensioner pulley bolt slackened, ensure
that the TDC marks on the camshaft
sprockets and the crankshaft pulley are
aligned as described in paragraph 6. If
necessary, turn the crankshaft to achieve
alignment.
37Have an assistant press the tensioner
pulley against the belt until the belt can just be
twisted through 45°, using moderate pressure
with the thumb and forefinger, on the longest
belt run between the exhaust camshaft
sprocket and the belt idler pulley.
38Have the assistant hold the tensioner
pulley in position, and tighten the tensioner
pulley bolt to the specified torque in the two
stages given in the Specifications.
39Turn the crankshaft clockwise through
two complete revolutions, 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.
40Proceed as described in paragraphs 30 to
34, inclusive.
41Have the belt tension adjusted by a
Vauxhall dealer using the manufacturer’s
special tool at the earliest opportunity.Adjustment using Vauxhall special
tool (KM-666)
42Proceed as described in paragraphs 35
and 36.
43Fit the special tool KM-666 to the belt
tensioner pulley mounting plate, in
accordance with the tool manufacturer’s
instructions.
44Working anti-clockwise from the TDC
mark on the exhaust camshaft sprocket, mark
the seventh tooth on the sprocket (see
illustration).
45Turn the crankshaft clockwise until this
tooth is aligned with the TDC notch in the
camshaft cover. The crankshaft must be
turned evenly and without jerking, to prevent
the timing belt from jumping off the sprockets
and pulleys.
46Tighten the tensioner pulley bolt to the
specified torque in the two stages given in the
Specifications.
47Remove the special tool.
DOHC engine procedures 2B•5
4.21 Belt tensioner pulley and spacer
sleeve. Note that smaller diameter of
spacer sleeve fits against pulley
4.44 Working anti-clockwise from the TDC
mark on the exhaust camshaft sprocket,
mark the seventh tooth on the sprocket4.24 Tightening a camshaft cover securing
bolt
4.19B Rear timing belt cover lower right-
hand securing bolt4.19A Timing belt outer cover screw upper
stud (1) and rear belt cover upper
securing bolts (2)
2B

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

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.

4Unscrew the bolt securing the crankcase
breather tube bracket to the end of the
cylinder head.
5Make a final check to ensure that all
relevant hoses, pipes and wires have been
disconnected.
6Continue as described in Section 8,
paragraphs 26 to 31.
Refitting
7Proceed as described in Section 8,
paragraphs 32 to 38 inclusive but in addition
note the following.
8On completion, check that all relevant
hoses, pipes and wires, etc., have been
reconnected.
10Cylinder head- dismantling
and reassembly
4
Dismantling
1With the cylinder head removed as
described in Section 8, clean away all external
dirt.
2If not already done, remove the thermostat
housing and thermostat as described in
Chapter 3, and remove the manifolds as
described in Chapters 4B and 4C.
3Remove the spark plugs (if not already
done), and remove the distributor with
reference to Chapter 5.
4Remove the camshafts as described in
Section 7.
5Remove the hydraulic valve lifters from their
bores using a rubber suction plunger tool - do
not invert the cylinder head to remove the
valve lifters. Keep the valve lifters upright at all
times (oil groove at bottom (see illustration)),
and immerse them in order of removal in a
container of clean engine oil until they are to
be refitted.
6To remove the valve components, continue
as described in Chapter 2A, Section 22,paragraphs 3 to 7 inclusive.
7The cylinder head and valves can be
inspected for wear and damage as described
in Chapter 2A, Section 23.
Reassembly
8With all components cleaned, refit the valve
components as described in Chapter 2A,
Section 22, paragraphs 10 to 19 inclusive.
9Refit the hydraulic valve lifters to the
cylinder head in their original positions.
Liberally oil the valve lifter bores, and if new
lifters are being fitted, initially immerse each
one in a container of clean engine oil and
compress it (by hand) several times to charge
it.
10Refit the camshafts, as described in
Section 7.
11Refit the spark plugs if desired, and refit
the distributor with reference to Chapter 5.
12Where applicable, refit the manifolds
and/or the thermostat and housing.
13Refit the cylinder head, as described in
Sections 8 and 9, as applicable.
11Valve lifters- general
Although the valve lifters on these engines
cannot be dismantled they should be carefully
inspected for obvious signs of wear on the
contact faces. Also check the valve lifter oil
holes for obstructions and for any signs of oil
sludge build-up. If excessive wear is evident
(this is unlikely), all the valve lifters must be
renewed as a set.
12Crankshaft front oil seal -
renewal
3
1The procedure is similar to SOHC models(see Chapter 2A), noting the following points.
2The spacer ring (if fitted), from the end of
the crankshaft, must be removed, before
refitting.
3After fitting the new seal, coat the oil pump
mating face of the spacer ring with sealing
compound, then push the spacer ring onto
the end of the crankshaft, until it is seated
against the oil pump.
4The timing belt should be renewed.
5Refit the rear timing belt cover and the
timing belt, as described in Section 4. Adjust it
as described in Section 4 and 5.
13Sump - removal and refitting
3
Note: Sump gaskets, cannot be reused.
Ensure that new gaskets are obtained before
removing the sump
Removal
1The procedure is similar to SOHC models
(see Chapter 2A), with the following variations.
2The engine undershield must be removed.
3Remove both the cork gaskets and clean all
sealing surfaces, scrupulously.
Refitting
4Locate a new gasket on the cylinder block,
if necessary applying a little sealing
compound to hold it in place.
5Locate the remaining new gasket on the
sump baffle, but do not use sealing
compound.
14Oil pump - removal and
refitting
3
Removal
1Apart from the following variations, the
procedure is the same as for SOHC models.
2If the engine is still in the vehicle,
disconnect the oil cooler pipe unions from the
oil pump, and move the pipes to one side out
DOHC engine procedures 2B•9
14.2 Oil cooler pipe unions at oil pump
10.5 Remove the hydraulic valve lifters using a rubber plunger. Inset (A) shows valve
lifter upright, with oil groove (arrowed) at bottom
2B