Ford Orion. Manual - part 29

8 Unscrew the retaining bolts, and remove
the water outlet from the thermostat housing
(see illustration).
9 Withdraw the thermostat from the housing
noting the position of the air bleed valve, and
how the thermostat is installed (which end is
facing outwards).

Testing

General check

10 Before assuming the thermostat is to
blame for a cooling system problem, check
the coolant level, auxiliary drivebelt tension
and condition (see Chapter 1) and
temperature gauge operation. When checking
the coolant level, don’t rely on the fact that the
expansion bottle is full - where possible,

remove the radiator cap and check the level in
the radiator.
11 If the engine seems to be taking a long
time to warm up (based on heater output or
temperature gauge operation), the thermostat
is probably stuck open. Renew the
thermostat.
12 If the engine runs hot, use your hand to
check the temperature of the radiator top
hose. If the hose isn’t hot, but the engine is,
the thermostat is probably stuck closed,
preventing the coolant inside the engine from
escaping to the radiator - renew the
thermostat. 

Caution: Don’t drive the vehicle
without a thermostat. The lack of
a thermostat will slow warm-up
time. The engine management

system’s ECU will then stay in warm-up
mode for longer than necessary, causing
emissions and fuel economy to suffer.

13 If the radiator top hose is hot, it means
that the coolant is flowing and the thermostat
is open. Consult the “Fault finding” section at
the end of this manual to assist in tracing
possible cooling system faults.

Thermostat test

14 If the thermostat remains in the open
position at room temperature, it is faulty, and
must be renewed as a matter of course.
15 To test it fully, suspend the (closed)
thermostat on a length of string in a container
of cold water, with a thermometer beside it;

ensure that neither touches the side of the
container (see illustration).
16 Heat the water, and check the
temperature at which the thermostat begins to
open; compare this value with that specified.
It’s not possible to check the fully-open
temperature, because this occurs above the
boiling point of water at normal atmospheric
pressure. If the temperature at which the
thermostat began to open was as specified,
then it is most likely that the thermostat’s OK.
Remove the thermostat, and allow it to cool
down; check that it closes fully.
17 If the thermostat does not open and close
as described, if it sticks in either position, or if
it does not open at the specified temperature,
it must be renewed.

Refitting

All models

18 Refitting is a reversal of removal. Clean
the mating surfaces carefully, and renew the
thermostat’s O-ring seal or housing gasket, as
applicable (see illustration).
19 On Zetec engines, ensure that the
thermostat is fitted with its air bleed valve
uppermost (see illustration).
20 Tighten the thermostat housing/water
outlet bolts to the specified torque wrench
setting.
21 Refill the cooling system (see Chapter 1).
22 Start the engine and allow it to reach
normal operating temperature, then check for
leaks and proper thermostat operation.

3•4 Cooling, heating and air conditioning systems

4.19  Ensure that the thermostat is fitted as

shown

4.18  Use a new gasket when refitting the

thermostat housing

4.15  Testing the thermostat

4.8  Unscrew the retaining bolts, and

remove the water outlet from the

thermostat housing

4.6C  . . . and where applicable, remove the

O-ring seal

4.6B  . . . extract the thermostat . . .

4.6A  Release the retaining clip . . .

5

Radiator electric cooling fan
assembly - testing, removal
and refitting

2

Note: Refer to the warnings given in Section 1
of this Chapter before starting work.

Testing

1 If it is suspected that the cooling fan is not
operating when high engine temperature
would normally require it to do so, first check
the relevant fuses and relays (see Chapter 12).
2 Detach the wiring multi-plug from the
thermostatic switch, which is located in the
thermostat housing on HCS and CVH
engines, or in the radiator top hose on Zetec
engines (see illustrations). Using a suitable
piece of wire, bridge the two connections
within the plug. Switch the ignition on and
check if the cooling fan operates. If the fan
now operates, the thermostatic switch is at
fault, and should be renewed as described in
Section 6. Remove the bridging wire from the
plug, and reconnect the wiring connector to
complete the test.
3 If the fan failed to operate in the previous
test, either the fan motor is at fault, or there is
a fault in the wiring loom (see Chapter 12 for
testing details).

Removal

Note:  Refer to Section 14 for removal and

refitting procedures on models equipped with
air conditioning.
4 Disconnect the battery negative (earth) lead
(refer to Chapter 5, Section 1).
5 Detach the wiring multi-plug from the fan
motor, and then unclip and remove the wiring
from the retaining clips on the shroud (see
illustrations). Also where applicable,
disconnect the coolant heater hose from the
location clips on the cooling fan shroud, or
unscrew the metal coolant pipe retaining
bolts.
6 Unscrew the two nuts (one each side)
securing the cooling fan shroud to the radiator
(see illustration).
7 Lift the fan unit complete with its shroud so
that the shroud is clear of the radiator

attachments, then lower and remove the
assembly from underneath the vehicle (see
illustration). Take care not to damage the
core of the radiator as the fan assembly is
withdrawn.
8 If required, the fan motor can be detached
from the shroud by unscrewing the three
retaining nuts (see illustration).

Refitting

9 Refitting is a reversal of the removal
procedure. Tighten the shroud-to-radiator
bolts and the fan-to-shroud nuts to the
specified torque setting. Ensure that the
wiring connection is cleanly and securely
made, and locate the loom in the retaining
clips.

Cooling, heating and air conditioning systems  3•5

5.5A  Detach the cooling fan motor wiring

connector . . .

5.2B  Cooling fan thermostatic switch

location (arrowed) in the radiator top hose

(Zetec engine)

5.2A  Cooling fan thermostatic switch

location (arrowed) in the thermostat

housing (CVH engine)

5.8  Fan motor-to-shroud nuts (arrowed)

5.7  Withdrawing the cooling fan shroud

and motor from under the vehicle

5.5C  . . . and from the locating clip

5.5B  . . . and release the wiring from the

shroud/motor support arm . . .

5.6  Cooling fan shroud-to-radiator

retaining nut 

3

6

Cooling system electrical
switches and sensors -
testing, removal and refitting

2

Note: Refer to the warnings given in Section 1
of this Chapter before starting work.

Coolant temperature gauge
sender

Testing

1 If the coolant temperature gauge is
inoperative, check the fuses first (see Chap-
ter 12).
2 If the gauge indicates overheating at any
time, consult the “Fault finding” section at the
end of this manual, to assist in tracing
possible cooling system faults.
3 If the gauge indicates overheating shortly
after the engine is started from cold, unplug
the coolant temperature sender’s electrical
connector. The sender is located below the
thermostat housing on HCS engines, adjacent
to the thermostat housing on CVH engines,
and on the forward-facing side of the
thermostat housing on Zetec engines. If the
gauge reading now drops, renew the sender.
If the reading remains high, the wire to the
gauge may be shorted to earth, or the gauge
is faulty.
4 If the gauge fails to indicate after the engine
has been warmed up (approximately 10
minutes) and the fuses are known to be
sound, switch off the engine. Unplug the
sender’s electrical connector, and use a
jumper wire to ground the connector to a
clean earth point (bare metal) on the engine.
Switch on the ignition without starting the
engine. If the gauge now indicates Hot, renew
the sender.
5 If the gauge still does not work, the circuit
may be open, or the gauge may be faulty. See
Chapter 12 for additional information.

Removal

6 Refer to Chapter 4 and remove the air
cleaner or air inlet hoses, according to engine
type as necessary, to gain access to the
sender unit.
7 Drain the cooling system (see Chapter 1).
8 On the Zetec engine, disconnect the
expansion tank coolant hose and the radiator
top hose from the thermostat housing’s water
outlet.
9 Unplug the electrical connector from the
sender unit.
10 Unscrew the sender and withdraw it.

Refitting

11 Clean as thoroughly as possible the sender
unit location, then apply a light coat of sealant
to the sender’s threads. Screw in the sender,
tighten it to the specified torque wrench
setting, and plug in its electrical connector.
12 Reconnect the hoses, and refit any
components disconnected for access. Top-
up the cooling system (see Chapter 1) and run
the engine. Check for leaks and proper gauge
operation.

Engine coolant temperature
sensor

Testing

13 Disconnect the battery negative (earth)
lead (see Chapter 5, Section 1).
14 Locate the coolant temperature sensor,
which will be found below the inlet manifold
on HCS engines, on the side or centre of the
inlet manifold on CVH engines, or on top of
the thermostat housing on Zetec engines.
Once located, refer to Chapter 4 and remove
the air cleaner or air inlet hoses, according to
engine type as necessary, to improve access
to the sensor unit.
15 Unplug the electrical connector from the
sensor.
16 Using an ohmmeter, measure the
resistance between the sensor terminals.
Depending on the temperature of the sensor
tip, the resistance measured will vary, but
should be within the broad limits given in the
Specifications Section of this Chapter. If the
sensor’s temperature is varied - by removing
it (see below) and placing it in a freezer for a
while, or by warming it gently - its resistance
should alter accordingly.
17 If the results obtained show the sensor to
be faulty, renew it.
18 On completion, plug in the connector and
refit any components removed for access,
then reconnect the battery.

Removal

19 Disconnect the battery negative (earth)
lead (see Chapter 5, Section 1).
20 Locate the sensor as described
previously, and remove any components as
necessary for access.
21 Drain the cooling system (see Chapter 1).
22 Unplug the electrical connector from the
sensor.
23 Unscrew the sensor and withdraw it.

Refitting

24 Clean as thoroughly as possible the
sensor location, then apply a light coat of
sealant to the sensor’s threads. Refit and
tighten the sensor to the specified torque
wrench setting, and plug in its electrical
connector.
25 Top-up the cooling system (see Chap-
ter 1) and run the engine, checking for leaks.

Radiator electric cooling fan
thermostatic switch

Testing

26 Refer to the procedures contained in
Section 5.

Removal

27 Disconnect the battery negative (earth)
lead (refer to Chapter 5, Section 1).
28 Drain the cooling system (see Chapter 1).
29 Disconnect the wiring multi-plug from the
thermostatic switch, and then unscrew the
switch from the thermostat housing or
radiator top hose, as applicable. Remove the
sealing washer.

Refitting

30 Refitting is a reversal of removal, but fit a
new sealing washer and tighten the switch
securely. Refill the cooling system as
described in Chapter 1, then reconnect the
battery.

7

Radiator and expansion tank
- removal, inspection and
refitting

1

Note: Refer to the warnings given in Section 1
of this Chapter before starting work.

Radiator

Removal

Note: If leakage is the reason for removing the
radiator, bear in mind that minor leaks can
often be cured using a radiator sealant with
the radiator in situ.
1 Disconnect the battery negative (earth) lead
(refer to Chapter 5, Section 1).
2 On carburettor engines, refer to Chapter 4A
and remove the air cleaner inlet if necessary,
for access.
3 Drain the cooling system (see Chapter 1).
4 Remove the cooling fan assembly as
described in Section 5.
5 Apply the handbrake, then raise and
support the vehicle at the front end on axle
stands.
6 Loosen off their retaining clips, and detach
the top, bottom and expansion tank hoses
from the radiator (see illustrations).

3•6 Cooling, heating and air conditioning systems

7.6A  Detach the top hose . . .

7.6B  . . . the bottom hose and expansion

tank hose from the radiator

7 Where applicable, disconnect the
automatic transmission fluid cooling pipes
from the radiator - be prepared for fluid loss
(see illustration). As they are disconnected,
plug the fluid hoses and connections, to
prevent further loss of fluid and the ingress of
dirt into the system. If air conditioning is fitted,
remove the splash shield (see paragraph 9),
then undo the three retaining nuts and detach
the air conditioning condenser from the side
of the radiator side deflector (see
illustration).
8 Unscrew the two retaining bolts on each
side of the radiator (underneath the radiator),
then supporting it, lower the radiator clear of
the mounting studs at the top, and carefully
withdraw it from underneath the front end of
the vehicle (see illustration).
9 Detach the rubber mounts, the side

deflectors and the bottom mounting from the
radiator. If required, the splash shield can be
removed from the radiator by undoing the six
retaining screws or drilling out the pop-rivets
and extracting the retaining clips (according
to type) (see illustrations).
10 With the radiator removed, it can be
inspected for leaks and damage. If it needs
repair, have a radiator specialist or dealer
service department perform the work, as
special techniques are required.
11 Insects and dirt can be removed from the
radiator with a garden hose or a soft brush.
Don’t bend the cooling fins as this is done.

Refitting

12 Refitting is a reversal of removal, but
check the mounting bushes, and if necessary
renew them. If the splash shield was detached
from the base of the radiator, refit it using new
pop-rivets or retaining clips, according to type
(see illustration). Refill the cooling system
with reference to Chapter 1. On automatic
transmission models check, and if necessary
top-up, the automatic transmission fluid level.

Expansion tank

Removal

13 Partially drain the cooling system, so that
the coolant level drops below the expansion
tank. Refer to Chapter 1 for details.
14 Where fitted, withdraw the power steering
fluid reservoir from the side of the expansion
tank, and move it aside as far as the hoses will
permit.

15 Before disconnecting the coolant hoses
from the expansion tank, it is advisable to
clamp them just short of their connections to
the expansion tank, to prevent spillage of
coolant and the ingress of air when they are
detached.
16 Loosen off the coolant hose clips at the
expansion tank, and detach the hoses from it.
If they are not clamped, secure them so that
their ends are raised, to minimise coolant
spillage.
17 Unscrew the two retaining screws, and
remove the expansion tank from the inner
wing panel.

Refitting

18 Refit in the reverse order of removal. Top-
up the cooling system as described in
Chapter 1.

8

Water pump (HCS engine) -
removal and refitting

1

Note: Refer to the warnings given in Section 1
of this Chapter before starting work.

Removal

1 Disconnect the battery negative (earth) lead
(refer to Chapter 5, Section 1).
2 Drain the cooling system (see Chapter 1).
3 Slacken the water pump pulley retaining
bolts, then remove the auxiliary drivebelt as
described in Chapter 1 (see illustration).

Cooling, heating and air conditioning systems  3•7

7.8  Radiator retaining bolts (arrowed)

7.9A  Radiator mounting rubber

7.7B  Air conditioner condenser retaining

nuts (arrowed)

7.7A  Automatic transmission fluid cooling
pipe connections to the radiator (arrowed)

8.3  Slacken the water pump drivebelt

pulley retaining bolts (arrowed) while the

drivebelt is still in place

7.12  Pop-riveting the anti-splash shield to

the radiator

7.9B  Drilling out a radiator-to-splash

shield rivet

3