Compression Test; Leakdown Test; Open The Cover On The Fuse/Relay Box; Remove The Fuel Pump Relay - Opel Zafira B MPV 2006 Owners Workshop Manual

How to use this Chapter
This Part of Chapter 2 describes the
repair procedures which can reasonably be
carried out on the engine while it remains in
the vehicle. If the engine has been removed
from the vehicle and is being dismantled as
described in Chapter 2E, any preliminary
dismantling procedures can be ignored.
Note that, while it may be possible physically
to overhaul items such as the piston/connecting
rod assemblies while the engine is in the
vehicle, such tasks are not usually carried out
as separate operations, and usually require the
execution of several additional procedures (not
to mention the cleaning of components and
of oilways); for this reason, all such tasks are
classed as major overhaul procedures, and are
described in Chapter 2E.
Chapter 2E describes the removal of the
engine/transmission unit from the vehicle, and
the full overhaul procedures which can then
be carried out.
Engine description
The 1.9 litre SOHC diesel engine is of
the eight-valve, in-line four-cylinder, single
overhead camshaft type, mounted transversely
at the front of the car, with the transmission on
its left-hand end.
The crankshaft is supported within the
cylinder block on five shell-type main bearings.
Thrustwashers are fitted to number 3 main
bearing, to control crankshaft endfloat.
The connecting rods rotate on horizontally-
split bearing shells at their big-ends. The
pistons are attached to the connecting rods by
gudgeon pins, which are retained by circlips.
The aluminium-alloy pistons are fitted with
three piston rings - two compression rings
and scraper-type oil control ring.
The camshaft runs directly in the cylinder
head, and is driven by the crankshaft via a
toothed composite rubber timing belt (which
also drives the high-pressure fuel pump and
the coolant pump). The camshaft operates
each valve via a camshaft follower with
adjustment shim.
Lubrication is by pressure-feed from a
rotor-type oil pump, which is mounted on the
right-hand end of the crankshaft. The pump
draws oil through a strainer located in the sump,
and then forces it through an externally mounted
full-flow cartridge-type filter. The oil flows into
galleries in the cylinder block/crankcase, from
where it is distributed to the crankshaft (main
bearings) and camshaft. The big-end bearings
are supplied with oil via internal drillings in the
crankshaft, while the camshaft bearings also
receive a pressurised supply. The camshaft
lobes and valves are lubricated by splash, as are
all other engine components.
A semi-closed crankcase ventilation system
1.9 litre SOHC diesel engine in-car repair procedures 2C•3
is employed; crankcase fumes are drawn from
the oil separator (integral with the camshaft
cover), and passed via a hose to the intake
manifold.
Operations with engine in car
The following operations can be carried out
without having to remove the engine from the
vehicle.
a) Removal and refitting of the camshaft cover.
b) Adjustment of the valve clearances.
c) Removal and refitting of the cylinder head.
d) Removal and refitting of the timing belt,
tensioner; idler pulleys and sprockets.
e) Renewal of the camshaft oil seal.
f) Removal and refitting of the camshaft and
followers.
g) Removal and refitting of the sump.
h) Removal and refitting of the connecting
rods and pistons.*
i) Removal and refitting of the oil pump.
j) Removal and refitting of the oil filter
housing.
k) Renewal of the crankshaft oil seals.
I) Renewal of the engine mountings.
m) Removal and refitting of the flywheel.
* Although the operation marked with an
asterisk can be carried out with the engine
in the car (after removal of the sump), it is
preferable for the engine to be removed, in the
interests of cleanliness and improved access.
For this reason, the procedure is described in
Chapter2E.
Compression
test
Note: A compression tester specifically
designed for diesel engines must be used for
this test.
1 When engine performance is down, or if
misfiring occurs which cannot be attributed
to the fuel system, a compression test can
provide diagnostic clues as to the engine's
condition. If the test is performed regularly, it
can give warning of trouble before any other
symptoms become apparent.
2 The tester is connected to an adapter
which screws into the injector holes. It is
2.3a Open the cover on the fuse/relay
box ...
unlikely to be worthwhile buying such a tester
for occasional use, but it may be possible
to borrow or hire one - if not, have the test
performed by a Vauxhall/Opel dealer, or
suitably-equipped garage.
3 Unless specific instructions to the contrary
are supplied with the tester, observe the
following points:
a) The battery must be in a good state of
charge, the air filter must be clean, and
the engine should be at normal operating
temperature.
b) All the fuel injectors must be removed
before starting the test (see Chapter 48).
c) Open the cover on the engine
compartment fuse/relay box and remove
the fuel pump relay (see illustrations).
4 Screw the compression tester and adapter
in to the fuel injector hole of No 1 cylinder.
5 With the help of an assistant, crank the
engine on the starter motor; after one or two
revolutions, the compression pressure should
build-up to a maximum figure, and then
stabilise. Record the highest reading obtained.
6 Repeat the test on the remaining cylinders,
recording the pressure in each.
7
All
cylinders should produce very similar
pressures; any difference greater than· the
maximum figure given in the Specifications
indicates the existence of a fault. Note that
the compression should build-up quickly in
a healthy engine; low compression on the
first stroke, followed by gradually-increasing
pressure on successive strokes, indicates
worn piston rings. A low compression reading
on the first stroke, which does not build-up
during successive strokes, indicates leaking
valves or a blown head gasket (a cracked head
could also be the cause). Note: The cause of
poor compression is Jess easy to establish
on
a
diesel engine than on
a
petrol one. The
effect of introducing oil into the cylinders
('wet' testing) is not conclusive, because there
is
a
risk that the oil will sit in the recess on the
piston crown instead of passing to the rings.
8 On completion of the test, refit the fuel
pump relay, then refit the fuel injectors as
described in Chapter 48.
Leakdown test
9 A leakdown test measures the rate at which
compressed air fed into the cylinder is lost. It
2.3b ... and remove the fuel pump relay
(arrowed)