Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
- Cooling system
   Check of level of cooling liquid
   Frost resistance check
   Check of the cooling system on tightness
   Carving cover of a broad tank
   List of malfunctions
   Water pump
   Maple belt of the water pump
   Cooling system fan
   Malfunctions of the fan of the cooling system
   List of malfunctions
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ System of injection
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications


If to speak simply, the thermostat defines, cooling liquid will or not circulate. That is, it defines, whether cooling liquid should pass on a small or big contour (see about it also at the beginning of this chapter). Naturally, the thermostat operates a stream of cooling liquid depending on its temperature. It occurs by means of the sleeve filled with special wax and the plate strengthened on it of the valve.

On an illustration the water pump and the case of the thermostat are shown in a section in order that you could glance inside. The bladed wheel (1) water pump is clearly visible. A row located the thermostat (2).

After removal of a cover of the case (3) on the left side of the engine the 5-cylinder engine has an access to the thermostat (2). The position (1) shows the water pump.

When heating cooling liquid wax thaws, extends and opens a plate of the valve. Until temperature of cooling liquid rises, the thermostat opens access to cold water from a radiator more and more. If working temperature, on the contrary, falls, the spring in the thermostat again presses a plate of the valve in situation "is closed" ("zu"), closing thereby access to cold water before working temperature.