The cooling system of the car is intended for maintenance of normal temperature of the engine by withdrawal of excess heat from the heating-up elements of the engine and dispersion of heat in the atmosphere.

The cooling system of tight type consists of the pump, a radiator, a broad tank, the electric fan, a radiator, the thermostat and the hoses connecting them. The system works as follows: until the engine cold – the thermostat is closed and cooling liquid circulates on a small circle, passing a radiator. Thus, bystry and economic warming up of the engine up to the working temperatures is provided. When temperature of cooling liquid reaches about 85 °C, the thermostat is slightly opened and liquid begins to circulate on a big circle through a radiator. At achievement of temperature of 105 °C the thermostat opens completely.

Heated cooling liquid passes through a heater radiator, warming up salon, and comes back to the pump. The liquid passing through a radiator is cooled with a counter flow of air. The electric fan of cooling of a radiator installed behind a radiator is run by the thermal sensor located in the left lower part of a radiator.

In addition to the ordinary sensor of the index of temperature of cooling liquid, temperature switches and sensors for ensuring work of system of injection of fuel and system of ignition are installed.

Fig. 4.1. SOHC engine cooling system: 1 – radiator; 2 – thermostat; 3 – connecting branch pipe; 4 – broad tank; 5 – top cover;    6 – air inlet; 7 – arm of the fan (EZ); 8 – arm of the fan (PB, RP); 9 – arm of fans; 10 – additional fan; 11 – driving belt; 12 – electric fan

Fig. 4.2. DOHC engine cooling system: 1 – radiator; 2 – pump; 3 – thermostat; 4 – a broad tank; 5 – oil heat exchanger; 6 – back cover; 7 – fan arm; 8 – arm of fans; 9 – electric fan; 10 – additional fan; 11 – driving belt; 12 – top cover; 13 – air inlet

Fig. 4.3. Cooling system of the diesel engine: 1 – radiator; 2 – pump of cooling liquid; 3 – thermostat; 4 – oil heater; 5 – electric pump; 6 – broad tank; 7 – turbocharger hose; 8 – cover; 9 – arm; 10 – electric fan of a radiator; 11 – additional fan of a radiator; 12 – belt; 13 – casing

Apparently from figures 4.1, 4.2 and 4.3 the design of the cooling system depends on type of the engine installed on the car.

PREVENTIONS 1. When opening a cover of a broad tank on the hot engine, it is necessary to be careful as the coming-out hot vapors can lead to severe burns 2. Do not allow hit of cooling liquid on clothes and a paint and varnish covering of a body. Otherwise wash out a surface a plentiful amount of water 3. It is not necessary to switch off the engine as the pump of cooling liquid will stop at that time after a long trip or when the engine worked at the limit modes at once. as superheated details of the engine continue to give heat that can lead to boiling of cooling liquid.

Specifications and characteristics