5.3.1. Excessive pressure and fan of a radiator
The cooling system is under pressure. Thereby, and also thanks to antifreeze additive the boiling point of cooling liquid raises to +126 °C. More high temperature promotes more economic operation of the engine. Excessive pressure in the cooling system makes about 1,4-1,5 bars. If at the heated engine pressure increases up to the bigger size, the reducing valve of a broad tank in a cover (fig. 4.41) works. At an overheat the fan in addition turns on.
Engines are equipped or the fan with viskomufty, or the electric fan. These units turn on from a bimetallic thermoswitch in case temperature of the proceeding liquid exceeds a certain value. The switch switches-off the fan when temperature of cooling liquid falls to safe level.
PREVENTION
The electric fan of a radiator can turn on also at the switched-off ignition because of aerodynamic heating of the engine.
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TECHNICAL DICTIONARY
Cooling system knots
Water pump. The centrifugal pump providing circulation of cooling liquid. At the 4-cylinder engine the water pump is on the same to a shaft, as the fan. At the 6-cylinder engine the water pump is installed on the left side of the engine on 4 bolts.
Radiator. All radiators are made of light alloy. Radiators, as well as a fan casing, have various dimensions. At cars with the automatic transmission at the right water tank of a radiator the crane of discharge of cooling liquid is installed.
Thermostat. This regulator depending on temperature operates contours of circulation of cooling liquid.
Contour at a temperature up to +85 °C: cooling liquid circulates on a small contour.
Contour of normal work at temperatures of +85... +100 °C: partially the radiator opens; cold liquid from a radiator mixes up with warm cooling liquid before she the pump moves in the engine.
The maximum cooling at a temperature above +100 °C: the valve of the thermostat is completely open, all cooling liquid passes through a radiator.
Broad tank. Pits steam at emergence of excessive pressure via the reducing valve in a cover.
Radiator fan. Depending on the engine, and also from equipment of the car, the fan with viskomufty or the electric fan is installed.
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Additional fan
If on your car the conditioner is installed, then before a radiator are established two connected with each other by means of a fan belt, and the fan located at the left is supplied with an electric motor from which the right fan also works.