General Information And Precautions; Cooling System Hoses; Radiator - Opel Zafira B MPV 2006 Owners Workshop Manual

3•2 Cooling, heating and air conditioning systems
General information
The cooling system is of pressurised type,
comprising a coolant pump, a crossflow
radiator, electric cooling fan, and thermostat.
The coolant pump is driven by the auxiliary
drivebelt on 1.6 and 1.8 litre petrol engines.
On 2.2 litre petrol engines, the coolant pump
is driven by the balancer shaft drive chain. On
diesel engines, the coolant pump is driven by
the timing belt.
The system functions as follows. Cold
coolant from the radiator passes through the
bottom hose to the coolant pump, where it
is pumped around the cylinder block, head
passages and heater matrix. After cooling
the cylinder bores, combustion surfaces and
valve seats, the coolant reaches the underside
of the thermostat, which is initially closed.
The coolant passes through the heater, and is
returned to the coolant pump.
When the engine is cold, the coolant
circulates only through the cylinder block,
cylinder head and heater. When the coolant
reaches a predetermined temperature, the
thermostat opens and the coolant also passes
through to the radiator. As the coolant circulates
through the radiator, it is cooled by the inrush
of air when the car is in forward motion. Airflow
is supplemented by the action of the electric
cooling fan when necessary. Once the coolant
has passed through the radiator, and has
cooled, the cycle is repeated.
On 1.6 litre and 1.8 litre petrol engines,
an electrically-assisted thermostat is fitted.
Engine coolant temperature is monitored by
the engine management system electronic
control unit, via the coolant temperature
sensor. In conjunction with information
received from various other engine sensors,
the thermostat opening temperature can be
controlled according to engine speed and
load. During normal engine operation the
thermostat operates conventionally. Under
conditions of high engine speed and load, an
electric heating element within the thermostat
is energised, to cause the thermostat to open
at a lower temperature (typically 90°).
The electric cooling fan, mounted on the
rear of the radiator, is controlled by the engine
management system electronic control unit,
in conjunction with a cooling fan module. At a
predetermined coolant temperature, the fan is
actuated.
An expansion tank is fitted to the
left-hand side of the engine compartment to
accommodate expansion of the coolant when
hot.
Precautions
A_
Warning: Do not attempt to
~
remove the expansion tank filler
cap, or disturb any part of the
cooling system, while the engine is hot;
there is a high risk of scalding. If the cap
must be removed before the engine and
radiator have fully cooled {even though this
is not recommended) the pressure in the
cooling system must first be relieved. Cover
the cap with
a
thick layer of cloth, to avoid
scalding, and slowly unscrew the filler cap
until a hissing sound can be heard. When
the hissing has stopped, indicating that the
pressure has reduced, slowly unscrew the
filler cap until it can be removed; if more
hissing sounds are heard, wait until they
have stopped before unscrewing the cap
completely. At all times, keep well away
from the filler cap opening.
Warning: Do not allow antifreeze
to come into contact with the skin,
or with the painted surfaces of the
vehicle. Rinse off spills immediately, with
plenty of water. Never leave antifreeze lying
around in an open container, or in a puddle
on the driveway or garage floor. Children
and pets are attracted by its sweet smell,
but antifreeze can be fatal if ingested.
A
Warning: If the engine is hot, the
electric cooling fan may start
rotating even if the engine is not
running; be careful to keep hands, hair and
loose clothing well clear when working in
the engine compartment.
Warning: Refer to Section 10 for
precautions to be observed when
working on models equipped with
air conditioning.
Note: Refer to the warnings given in Section 1
of this Chapter before proceeding. Do not
attempt to disconnect any hose while the
system is still hot.
1 If the checks described in Chapter 1 A or 1 B
reveal a faulty hose, it must be renewed as
follows.
2 First drain the cooling system (see Chap-
ter 1 A or 1 B). If the coolant is not due for
renewal, it may be re-used if it is collected in a
clean container.
3 Before disconnecting a hose, first note
its routing in the engine compartment, and
whether it is secured by any additional
retaining clips or cable ties. Use a pair of
pliers to release the clamp-type clips, or a
screwdriver to slacken the screw-type clips,
then move the clips along the hose, clear of
the relevant inlet/outlet union. Carefully work
the hose free.
4 Note that the radiator inlet and outlet unions
are fragile; do not use excessive force when
attempting to remove the hoses. If a hose
proves to be difficult to remove, try to release
it by rotating the hose ends before attempting
to free it.
5 When fitting a hose, first slide the clips onto
the hose, then work the hose into position.
If clamp-type clips were originally fitted, it is
a good idea to use screw-type clips when
refitting the hose. If the hose is stiff, use a little
soapy water (washing-up liquid is ideal) as a
lubricant, or soften the hose by soaking it in
hot water.
6 Work the hose into position, checking that
it is correctly routed and secured. Slide each
clip along the hose until it passes over the
flared end of the relevant inlet/outlet union,
before tightening the clips securely.
7 Refill the cooling system with reference to
Chapter 1A or 1 B.
8 Check thoroughly for leaks as soon as
possible after disturbing any part of the
cooling system.
3 .
Radiator- . . . .
removal,. inspect!gl •
. aoo.reflt,tlns.
Petrol engine models
Removal
1 Disconnect the battery negative terminal
(refer to Disconnecting the battery in the
Reference Chapter).
2 Remove the front bumper as described in
Chapter 11.
3 Drain the cooling system as described in
Chapter 1A.
4 Disconnect the cooling fan wiring harness
connector from the base of the fan housing.
Free the wiring harness from the cable ties.
5 On 1.6 and 1.8 litre models, disconnect the
wiring connector at the coolant temperature
sensor in the radiator side tank. Free the
wiring harness from the cable ties.
6 On models with an auxiliary cooling fan
mounted in front of the radiator, unclip
the two relays from the top of the fan
housing. Disconnect the fan wiring harness
connector from the base of the fan housing,
then undo the bolt securing the harness to
the housing. Free the wiring harness from
the cable ties.
7 Release the retaining clips and disconnect
the top and bottom hoses and expansion tank
hose from the radiator. Release the hoses
from the radiator and fan housing supports.
8 On 1.6 and 1.8 litre models, undo the bolt
each side securing the fan housing to the top
of the radiator. Lift the fan housing up and out
of the lower mounting brackets and remove
the fan housing from the car.
9 On models with automatic transmission,
undo the union bolts and disconnect the
upper and lower fluid cooler pipe unions at
the radiator. Recover the seals.
10 Retain the radiator in position by inserting
a drill bit or similar, through the holes provided
on each of the radiator upper mounting
brackets
(see illustration}.
11 On models with air conditioning, secure
the condenser to the bonnet crossmember
with cable ties. Undo the upper and lower