Audi 80/Avant (B4)

since 1991-1995 of release

Repair and car operation

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 okhladitelny 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 at present time:

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

The system of cooling calculated on work at superfluous pressure

In cooling system at working temperature the elevated pressure 1,2 – 1,5 bar that increases temperature of boiling of cooling liquid much above 100°С dominates. Thereby a certain reserve is created. The engine can reach the working temperatures exceeding 100°С, and thus in system of cooling 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 a safety valve (1,2 – 1,5 bar) and the vacuum valve (0,06 – 0,1 bar). The vacuum valve lets in air if cooling liquid becomes colder and by that takes less place.