2892425 - Introduction - ENGINE COOLING

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1, Water pump 2, Heater unit 3, Engine coolant temperature sensor (see 1060) 4, Thermostat 5, Radiator 6, Electric fans 7, Supply reservoir 8, Rigid water inlet pipe to pump 9, Water-oil exchanger

RESERVOIR

In addition to supplying the system, the reservoir also absorbs the variations in volume of the cooling liquid, as the engine temperature varies.

Through a specific calibrated valve, contained in the pressurized cap:

  • air emerges from the collection circuit from the pipe coming from the thermostat
  • air enters when the circuit is in a vacuum (because of the engine cooling).

RADIATOR (VERSION WITH HEATER)

This consists of a radiating mass and two side chambers acting as the coolant to inlet and outlet. The coolant inlet and outlet pipes are connected to the left reservoir, in order to convey the fluid along a C-shaped route in the radiating mass.The tubes and fins of the radiating mass are of aluminium, and the reservoirs are of plastic.

RADIATOR (VERSION WITH AIR CONDITIONING)

This consists of a radiating mass and two side chambers, one top and one bottom, for circulation of the coolant. The coolant inlet and outlet pipes are connected to the top reservoir, in order to convey the fluid along a U-shaped route in the radiating mass. The tubes and fins of the radiating mass and the reservoirs are of metal.

WATER PUMP

It is the centrifugal vane type, with an aluminium alloy pump casing and phenolic resin impeller.Secured to the engine block and driven directly by the timing belt.

THERMOSTAT

Mounted on the rear of the cylinder head, its function is to keep the engine at the optimum temperature:

  • at a temperature of < 80 ± 2°C the (closed) thermostatic valve directs the coolant directly to the pump
  • at a temperature of > 80 ± 2°C the (open) thermostatic valve directs the coolant to the radiator.
Mounted on the thermostat, there is the coolant temperature sensor connected to the fuel injection control unit (see 1060).