The sealed type cooling system includes a belt driven water pump, thermoviscous clutch radiator fan, radiator, expansion tank, heater thermostat and radiator, as well as hoses and switches.
To cool the engine, the water pump keeps the coolant flowing continuously. On a cold engine, coolant circulates through the cylinder head, engine block, and interior heater core. When the temperature of the coolant rises, the thermostat opens a large circulation circuit. In this case, the coolant also passes through the radiator, and its temperature decreases due to the air flow blowing the radiator.
The amount of air flow is increased by a fan located behind the radiator. The fan is driven by a V-ribbed belt from the crankshaft pulley. Thermoviscous coupling (viscous coupling) The radiator fan turns on depending on the temperature of the air behind the radiator. When the predetermined temperature is reached, the valve in the clutch opens and the thermoviscous clutch drives the fan impeller, as a result, the radiator airflow increases. The fan speed cannot exceed the engine speed. Depending on the design, for example, in the presence of an air conditioner, an additional electric fan is installed. It is controlled by a two-stage thermal sensor, which is screwed to the lower left side of the radiator. When the coolant temperature is from +92°C to +98°C, the temperature sensor turns on the fan to the first stage (low speed). If the coolant temperature rises to +99... +105°C, the fan turns on at maximum speed.
As a result of intermittent fan operation and thermostatic control of coolant flow, engine operating temperature is reached faster with reduced fuel consumption.
The electrically driven fan can also be switched on when the ignition is switched off. When working on a hot engine, temporarily disconnect the fan connector.
Attention
- The electrically driven fan may also turn on after the ignition is turned off. Therefore, when working on a hot engine, it is necessary to disconnect the electrical connector from the fan motor for the duration of the work.
- When working on the cooling system, be careful not to get coolant on the toothed belt. Ethylene glycol contained in the coolant can damage the toothed belt material, which can lead to belt breakage during further operation.
Pic. 3.1. Elements of the cooling system of gasoline engines 1.8-I
1 - radiator,
2 - upper radiator hose,
3 - water pump / thermostat,
4 - cylinder head,
5 - heat exchanger (radiator) heater,
6 - coolant return pipe,
7 - throttle assembly,
8 - expansion tank,
9 - oil heat exchanger,
10 - intake manifold.
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