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Chapter 2 cooling and heating systems, Specifications contents, Degrees of difficulty – FIAT Uno 45 User Manual

Page 51

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2

System type

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

“No loss” with radiator and integral expansion tank. Electric cooling
fan, belt-driven coolant pump, thermostat on cylinder head

General

Radiator fan cuts in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

90 to 94ºC (194 to 201ºF)

Radiator fan switches off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

85 to 89ºC (185 to 192ºF)

Thermostat opens:

903 cc engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

85 to 89ºC (185 to 192ºF)

1116 cc and 1301 cc engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

83 to 87ºC (181 to 188.6ºF)

Fully open:

903 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

100ºC (212ºF)

1116 cc and 1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

95ºC (203ºF)

Expansion tank pressure cap rating . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.78 bar (11 lbf/in2)

Coolant

Capacity:

903 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.6 litre (8.1 pint)

1116 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.0 litre (10.6 pint)

1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.2 litre (10.9 pint)

Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ethylene glycol based antifreeze

Torque wrench settings

Nm

lbf ft

Temperature sender switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

49

36

Coolant pump mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

25

Alternator adjuster and mountings nuts . . . . . . . . . . . . . . . . . . . . . . . . .

49

36

Chapter 2 Cooling and heating systems

For modifications, and information applicable to later models, see Supplement at end of manual

Coolant mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

Coolant pump - removal, overhaul and refitting . . . . . . . . . . . . . . . .

9

Cooling system - draining, flushing and refilling . . . . . . . . . . . . . . . .

2

Cooling system sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Description and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

Drivebelt - tensioning and renewal . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Fault finding - cooling and heating . . . . . . . . . . . . See end of Chapter

Heater - dismantling, overhaul and reassembly . . . . . . . . . . . . . . . . 13
Heater unit - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Heating and ventilation system - description . . . . . . . . . . . . . . . . . . 11
Radiator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Radiator fan thermostatic switch - removal, checking and refitting .

5

Radiator fan - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . .

6

Thermostat - removal, testing and refitting . . . . . . . . . . . . . . . . . . . .

4

2•1

Specifications

Contents

1

Description and
maintenance

1

1 The cooling system consists of a
front-mounted radiator with built-in expansion
tank, a coolant pump (belt-driven from the
crankshaft pulley) and a thermostatically-
controlled electric cooling fan.
2 In order to assist rapid warm-up, a

thermostat is located in a housing at the
left-hand end of the cylinder head. The hose
connections to the thermostat housing vary
according to model.
3 The heater is supplied with coolant from the
engine and incorporates a matrix and blower
with the necessary controls.
4 The throttle valve plate block of the
carburettor is coolant-heated as a means of
improving fuel atomisation.
5 Maintenance is minimal as in theory no
coolant should ever be lost from the

expansion tank. Regularly check that the
coolant level is between 50.0 and 70.0 mm
(1.97 and 2.8 in) above the MIN mark on the
tank with the engine cold. The need for
regular topping up will indicate a leak
somewhere in the system. If one cannot be
found suspect an internal leak in the engine
although this is usually confirmed by a rise in
the engine oil level and water on the dipstick
(photo). Any topping-up should be done using
an antifreeze mixture (see Section 3), not plain
water.

Easy, suitable for
novice with little
experience

Fairly easy, suitable
for beginner with
some experience

Fairly difficult,
suitable for competent
DIY mechanic

Difficult, suitable for
experienced DIY
mechanic

Very difficult,
suitable for expert DIY
or professional

Degrees of difficulty

5

4

3

2

1

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