Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

The cooling system in Audi 80 carries out two functions: cools the engine and warms salon. Usually it is very reliable but if after all there were malfunctions, this head will help you to deal with these problems.

So there is a cooling

At the working engine the water pump constantly pumps over cooling liquid on numerous cooling channels of the engine and deletes heat arising in cylinders at combustion.

The drive of the water pump in the 4-cylinder engine is provided with a maple belt, in the 5-cylinder engine a gear belt, and in the 6-cylinder engine – a poliklinovy belt.

The way of passing of cooling liquid depends on its temperature of time at present:

• If the engine did not reach working temperature yet, cooling liquid flows on the small contour passing through the engine and the heat exchanger. In addition to a small contour of cooling liquid the inlet collector is connected.
• On reaching temperature about 87 °C the thermostat opens a big contour which includes also a radiator. If temperature of cooling liquid rises further so even in a radiator temperature makes over 92 °C, into action goes the radiator fan, helping when cooling.

The cooling system calculated on work with an excessive pressure

In the cooling system at a working temperature the elevated pressure of 1,2 - 1,5 bars that increases temperature of boiling of cooling liquid above 100 °C dominates. Thereby a certain reserve is created. The engine can reach the working temperatures exceeding 100 °C and thus in the cooling system there is no danger of boiling.

The correct pressure in system is created thanks to a carving cover of a broad tank which is supplied with the safety valve (1,2 – 1,5 bars) and the vacuum valve (0,06 – 0,1 bars). The vacuum valve lets in air if cooling liquid becomes colder and by that takes less places.