radiator cap FORD SIERRA 1984 1.G Cooling And Air Conditioning Systems Workshop Manual

System type
SOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pressurised, with belt-driven coolant pump, crossflow radiator,
thermo-viscous fan, thermostat, and expansion tank
CVH and DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pressurised, with belt-driven coolant pump, crossflow radiator,
electric fan, thermostat, and expansion tank
Thermostat
Nominal temperature rating (fully open):
SOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88ºC (190º F)
CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100ºC (212ºF)
DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102ºC (216ºF)
Opening temperature:
SOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 to 89ºC (185 to 192ºF)
CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88ºC (190ºF)
CVH (R6A type) models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 to 89ºC (185 to 192ºF)
DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 to 89ºC (185 to 192ºF)
Expansion tank cap opening pressure
SOHC models:
Up to 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.85 to 1.1 bar (12 to 16 lbf/in2)
From 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 to 1.25 bar (15 to 18 lbf/in2)
CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 to 1.25 bar (15 to 18 lbf/in2)
DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 to 1.4 bar (15 to 20 lbf/in2)
Coolant mixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1 Specifications
System capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1 Specifications
Drivebelt tensions
Air conditioning system compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.0 mm (0.4 in) deflection at the midpoint of the belt’s longest run
under firm thumb pressure
Coolant pump/alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.0 mm (0.4 in) deflection midway between coolant pump and
alternator (or power steering pump) pulleys under firm thumb pressure
Chapter 3
Cooling, heating and air conditioning systems
Air conditioning system - component renewal . . . . . . . . . . . . . . . . . .21
Coolant pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . .9
Coolant pump/alternator drivebelt(s) - checking, renewal and
tensioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Coolant pump/alternator drivebelt tensioner (DOHC models with
power steering) - removal and refitting . . . . . . . . . . . . . . . . . . . . . .11
Cooling fan switch - removal and refitting . . . . . . . . . . . . . . . . . . . . .14
Cooling system - draining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Cooling system - filling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Cooling system - flushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Electric cooling fan - removal and refitting . . . . . . . . . . . . . . . . . . . . .13
Expansion tank and coolant level sensor - removal and refitting . . . .15General information and precautions . . . . . . . . . . . . . . . . . . . . . . . . . .1
Heater controls - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . .17
Heater motor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . .20
Heater unit - overhaul . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Heater unit - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Radiator - inspection and cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Radiator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Temperature gauge sender - removal and refitting . . . . . . . . . . . . . .16
Thermostat - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Thermostat - testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Thermo-viscous cooling fan (SOHC models) - removal and refitting .12
3•1
Specifications Contents3
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

Torque wrench settingsNmlbf ft
Radiator upper mounting nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2515 to 18
Radiator lower mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 126 to 9
Coolant pump bolts:
SOHC models:
M8 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 to 2113 to 15
M10 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 to 4226 to 31
CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 116 to 8
CVH (R6A type) models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 to 105 to 7
DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2815 to 21
Thermostat housing bolts:
SOHC/DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 to 2013 to 15
CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 116 to 8
CVH (R6A type) models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 126 to 9
Cooling fan shroud-to-radiator nuts/bolts . . . . . . . . . . . . . . . . . . . . . . .8 to 116 to 8
Coolant pump pulley bolts:
SOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2815 to 21
DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2515 to 18
Coolant pump/alternator drivebelt tensioner bolt:
CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 to 3017 to 22
DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 to 9752 to 72
Cooling fan blades-to-fan hub bolts (SOHC models) . . . . . . . . . . . . . . .8 to 106 to 7
Air conditioning compressor-to-bracket bolts . . . . . . . . . . . . . . . . . . . .65 to 7548 to 55
Air conditioning compressor bracket-to-engine bolts:
M10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 to 9263 to 68
M12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110 to 12081 to 89
Air conditioning condenser fan assembly-to-condenser bolts:
Models up to 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 to 31 to 2
Models from 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 116 to 8
Air conditioning condenser securing bolts (models from 1987) . . . . . . .27 to 3320 to 24
General information
The cooling system is of pressurised type,
and consists of a front mounted radiator,
coolant pump, cooling fan, wax type
thermostat, and an expansion tank.
The radiator matrix is manufactured from
honeycombed metal, and the end tanks are
made of plastic. On automatic transmission
models, the right-hand end tank incorporates
the transmission fluid cooler.
The coolant pump is located on the front
face of the engine block, and is belt-driven.
The pump is of the impeller type.
The cooling fan draws cold air over the
radiator matrix to assist the cooling process
when the forward speed of the vehicle is too
low to provide sufficient cooling airflow, or the
ambient temperature is unusually high. SOHC
models have a thermo-viscous fan, whereas
CVH and DOHC models have an
electrically-operated fan.
The thermo-viscous fan is controlled by the
temperature of the air behind the radiator.
When the air temperature reaches a
predetermined level, a bi-metallic coil
commences to open a valve within the unit,
and silicon fluid is fed through a system of
vanes. Half the vanes are driven directly by
the coolant pump, and the remaining half are
connected to the fan blades. The vanes are
arranged so that drive is transmitted to the fan
blades in relation to the viscosity of the silicon
fluid, and this in turn depends on ambienttemperature and engine speed. The fan is
therefore only operating when required, and
compared with direct-drive type fans
represents a considerable improvement in fuel
economy, drivebelt wear and fan noise.
The electrically-operated fan is switched on
by a temperature sensor mounted in the
thermostat housing when the temperature
reaches a predetermined level. The fan is
therefore only operating when required, and like
the thermo-viscous fan, offers a considerable
advantage over direct-drive type fans.
A thermostat is fitted. Its purpose is to
ensure rapid engine warm-up by restricting
the flow of coolant to the engine when cold
and also to assist in regulating the normal
operating temperature of the engine.
The expansion tank incorporates a pressure
cap which effectively pressurises the cooling
system as the coolant temperature rises,
thereby increasing the boiling point of the
coolant. The tank also has a further degas
function. Any accumulation of air bubbles in the
coolant is returned to the tank and released in
the air space, thus maintaining the efficiency of
the coolant. The pressure cap also incorporates
a vacuum relief valve which prevents a vacuum
forming in the system as it cools.
The system functions as follows. Cold
coolant in the bottom of the radiator circulates
through the bottom hose to the coolant pump
where the pump impeller pushes the coolant
through the passages within the cylinder
block, cylinder head and inlet manifold. After
cooling the cylinder bores, combustion
chambers and valve seats, the coolant
reaches the underside of the thermostat
which is initially closed. A small proportion ofthe coolant passes from the thermostat
housing to the expansion tank, but the main
circulation is through the inlet manifold,
automatic choke (where applicable), and
heater matrix, finally returning to the coolant
pump. When the coolant reaches a
predetermined temperature, the thermostat
opens and hot water passes through the top
hose to the top of the radiator. As the coolant
circulates through the radiator, it is cooled by
the flow of air to the vehicle’s forward motion,
supplemented by the action of the cooling fan
where necessary. By the time it reaches the
bottom of the radiator the coolant is cooled,
and the cycle is repeated. Circulation of
coolant continues through the expansion
tank, inlet manifold, automatic choke (where
applicable) and heater at all times, the heater
temperature being controlled by an air flap.
An air conditioning system is available as
an optional extra on certain models. In
conjunction with the heater, the system
enables any reasonable air temperature to be
achieved inside the vehicle; it also reduces
the humidity of the incoming air, aiding
demisting even when cooling is not required.
The refrigeration side of the air conditioning
system functions in a similar way to a
domestic refrigerator. A compressor, belt-
driven from the crankshaft pulley, draws
refrigerant in its gaseous phase from an
evaporator. The compressed refrigerant
passes through a condenser where it loses
heat and enters its liquid phase. After passing
through the dehydrator, which acts as a
reservoir and filter to extract moisture from
the circuit, the refrigerant returns to the
evaporator where it absorbs heat from the air
1General information and
precautions
3•2Cooling, heating and air conditioning systems

3A radiator specialist can perform a “flow
test” on the radiator to establish whether an
internal blockage exists.
4A leaking radiator must be referred to a
specialist for permanent repair. Do not
attempt to weld or solder a leaking radiator,
as damage to the plastic parts may result.
5In an emergency, minor leaks from the
radiator can be cured by using a sealant.
1Disconnect the battery negative lead.
2Drain the cooling system.
3Proceed as follows according to model:
SOHC models
4Disconnect the radiator top hose and
expansion tank hose from the thermostathousing situated at the front of the cylinder
head (see illustrations).
5Unscrew the two securing bolts and
remove the housing and gasket.
6Using a screwdriver, prise the retaining clip
from the housing, and extract the thermostat
and sealing ring (see illustrations).
7Refitting is a reversal of removal, bearing in
mind the following points.
8Clean the housing and the mating face of
the cylinder head. Check the thermostat
sealing ring for condition and renew it if
necessary. Use a new gasket when refitting
the housing.
9The thermostat wax capsule must face into
the cylinder head with the flow direction arrow
facing forward (see illustration).
10Refill the cooling system.CVH models
11Disconnect the wiring plug from thecooling fan switch on the thermostat housing
situated at the front of the inlet manifold.
12Disconnect the automatic choke hose,
radiator top hose and expansion tank hose
from the thermostat housing. Where
applicable, take care not to strain the wiring
which is routed around the housing. If
necessary, disconnect the wiring connector
(see illustrations).
13Unscrew the three securing bolts and
remove the housing and gasket (see
illustration).
14Lift the thermostat from the housing, and
carefully prise out the sealing ring.
15Refitting is a reversal of removal, bearing
in mind the following points.
16Clean the housing and the mating face of
the inlet manifold. Check the thermostat
sealing ring for condition and renew it if
necessary. Use a new gasket when refitting
the housing.
7Thermostat -removaland
refitting
3•4Cooling, heating and air conditioning systems
7.4a Radiator top hose connection at
thermostat housing7.6a Prise out the retaining clip . . .
7.12c . . . and the expansion tank hose7.12b . . . the radiator top hose . . .7.12a Disconnect the automatic choke
hose . . .
7.4b Disconnect the expansion tank hose
from the thermostat housing
7.6b . . . and extract the thermostat . . .7.9 Thermostat flow direction markings
(arrowed)7.6c . . . and sealing ring

17Note that the thermostat wax capsule
must face into the inlet manifold, with the flow
direction arrow pointing forward, in line with
the pressure relief valve in the housing (see
illustration).
18Refill the cooling system.
DOHC models
19On fuel injection models, for access to the
thermostat housing loosen the clips and
remove the air inlet tube which connects the
plenum chamber to the inlet manifold.
20Disconnect the coolant hoses from the
thermostat housing (see illustrations).
21Disconnect the wiring plug from the
cooling fan switch mounted in the thermostat
housing (see illustration).
22Unscrew the three securing bolts, and
withdraw the thermostat housing (see
illustration).
23Manipulate the thermostat from the inlet
manifold, and recover the O-ring. If it isnecessary to prise the thermostat out, take
care not to damage the surface of the housing
in the inlet manifold.
24Refitting is a reversal of removal, bearing
in mind the following points.
25Ensure that the O-ring seal is correctly
fitted around the edge of the thermostat.
26When fitting the thermostat to the inlet
manifold, ensure that the relief valve is located
in the 12 o’clock position (see illustration).
27Tighten the thermostat housing securing
bolts to the specified torque.
28Refill the cooling system.
1To test the thermostat, suspend it by a
piece of string in a container of water (see
illustration).2Gradually heat the water, and using a
thermometer with a range of at least 100ºC,
note the temperature at which the thermostat
starts to open.
3Remove the thermostat from the water and
check that it is fully closed when cold.
4Renew the thermostat if the opening
temperature is not as given in the
Specifications, or if the unit does not fully
close when cold.
1Disconnect the battery negative lead.
2Drain the cooling system.
3Proceed as follows according to model:
SOHC models
4Disconnect the heater and radiator bottom
hoses from the coolant pump.
5Remove the thermo-viscous fan (Section 12).
6If not already done, remove the coolant
pump drivebelt, then unscrew the four
retaining bolts and remove the coolant pump
pulley. If necessary, the pulley can be
prevented from turning using a strap wrench.
7Unbolt and remove the timing belt cover.
9Coolant pump - removal and
refitting
8Thermostat - testing
Cooling, heating and air conditioning systems 3•5
3
7.20a Disconnect the coolant hoses . . .
8.1 Testing the thermostat opening
temperature7.26 Thermostat relief valve (arrowed)
should be in the 12 o’clock position7.22 Withdrawing the thermostat housing
7.21 Disconnect the cooling fan switch
wiring plug7.20b . . . from the thermostat housing
7.17 Correct orientation of thermostat with
flow direction arrow pointing towards
pressure relief valve7.13 Removing the thermostat housing and
gasket
Holding the pulley can be
improvised using an old
drivebelt, and a suitable
socket and wrench.

DOHC models
6Disconnect the battery negative lead.
7To provide additional clearance when
removing the cooling fan shroud assembly
(which is removed from below the vehicle),
apply the handbrake, then jack up the front of
the vehicle and support it securely on axle
stands (see “Jacking and Vehicle Support”).
8Disconnect the wiring plug(s) from the
motor(s), and where applicable, unclip the
wiring from the fan shroud.
9Unclip the expansion tank hose from the
fan shroud.
10Unscrew the two nuts securing the fan
shroud to the top of the radiator, then tilt the
top of the shroud away from the radiator, and
lift the shroud to release the lower securing
clips. Withdraw the assembly from below the
vehicle.
11To remove the fan blades, prise the
securing clip from the end of the motor shaft.12The motor can be separated from the fan
shroud by unscrewing the three securing nuts
and bolts.
13Where two cooling fans are fitted, both are
secured to the shroud in the same manner.
14Refitting is a reversal of removal, but
when fitting the fan blades, ensure that the
drive dog on the motor shaft engages with the
slot in the rear of the fan blades.
On CVH models, the cooling fan switch is
located on the right-hand side of the
thermostat housing (see illustration). On
DOHC models, the switch is located in the
end of the thermostat housing.
Removal and refitting of the switch is as
described for the temperature gauge sender.
Removal
1With the engine cold, slowly unscrew the
expansion tank cap to release any remaining
pressure from the cooling system. Remove
the cap.
2Place a suitable container beneath the
expansion tank.
3Disconnect and plug the upper hose.
4Where applicable, disconnect the coolant
level sensor wiring plug. 5Unscrew the expansion tank securing
screws, and tilt the tank so that the coolant
runs to the sealed end.
6Disconnect and plug the lower hose.
7Drain the expansion tank into the container
and remove the tank.
8Where applicable, the coolant level sensor
can be removed from the tank by unscrewing
the collar from the sensor, then withdrawing
the spacer, sensor and seal (see illustration).
Renew the seal if necessary. Note that the
sensor can only be fitted in one position (see
illustration). Refitting
9Refitting is a reversal of removal.
10On completion, top-up the coolant level to
the maximum mark, then refit the expansion
tank cap and run the engine at a fast idling
speed for several minutes. Check the
expansion tank for leaks, then stop the engine
and if necessary top-up the coolant level.
Removal
1On SOHC models, the temperature gauge
sender is located on the front left-hand side of
the cylinder head, just in front of the inlet
manifold. On CVH models, the sender is
located on the front face of the inlet manifold,
next to the thermostat housing. On DOHC
models, the sender is located at the front of
the inlet manifold (see illustration).
16Temperature gauge sender
- removal and refitting
15Expansion tank and coolant
level sensor - removal and
refitting
14Cooling fan switch -removal
andrefitting
3•8Cooling, heating and air conditioning systems
13.2 Fan blade securing clip and direction
of rotation arrow
15.8a Removing the coolant level sensor
from the expansion tank
16.3a Disconnect the temperature gauge
sender wiring - SOHC16.1 Temperature gauge sender location
(arrowed)16.3b Disconnect the temperature gauge
sender wiring - CVH
15.8b Fitting the coolant level sensor
14.1 Disconnecting the wiring plug from
the cooling fan switch