Audi 80/Avant (B4)

since 1991-1995 of release

Repair and car operation

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 system of cooling on tightness
   Carving cover of a broad tank
   List of malfunctions
   Water pump
   Maple belt of the water pump
   Fan of system of cooling
   Malfunctions of the fan of system of cooling
   List of malfunctions
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ injection System
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrosystem
+ ignition System
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

List of malfunctions


Malfunction sign
A.Indikator of temperature rises slowly, the working temperature is reached later, insufficient heating effect The plate of the valve of the thermostat is blocked in situation "openly" («offen»), for example because of deposits; the stream to a radiator remains constantly open. The engine too long remains in a mode of operation of cold start. Within a short period of time there should be, however, no damages. Despite it, it is necessary to replace the thermostat as soon as possible.
V.Strelka of the temperature indicator completely deviated to the right, despite the correct level of liquid, the indicator of cooling liquid blinks. The radiator and the bottom tube to a radiator remain cold. The plate of the valve of the thermostat is blocked in situation "Is closed" («zu») (for example because of a faulty or not tight sleeve of the thermostat). It is not necessary to continue by no means movement, otherwise the engine can receive the most serious damages because of an overheat! Immediately to replace the thermostat. 

 Help: if the engine begins to boil on the road because of the faulty thermostat, can help either the wrecker, or thermostat removal on a place. If you decided to remove the thermostat, it is necessary to wait until the temperature of cooling means will not go down. At this time you can get capacities for plum of cooling liquid.

Thermostat removal

At the 6-cylinder engine the case of the thermostat (shooter) is located to the right of the block of cylinders.

Removal of the jammed thermostat on the way – quite problematic occupation. It is located quite deeply below so it is necessary to merge almost all okhladayushchy liquid. Besides at the hot engine it is necessary to wait long before it is possible to start to work, without being afraid to scald itself a hand. At installation of the new thermostat it is necessary to replace also sealing laying on the case of the thermostat or the water pump.


  1. Completely to merge cooling liquid.
  2. Models with 4-cylinder engines: to remove the bottom protection of a motor compartment (head body Elements).
  3. To remove a hose below on the case of the water pump (it was already made for plum of cooling liquid).
  4. To turn off two bolts on a cover in the lower part of the case of the thermostat.
  5. To uncover and the thermostat.
  6. Models with 5-cylinder engines: to turn off two bolts on a cover of the case of the thermostat.
  7. To press on a cover aside and to remove the thermostat.
  8. Models with 6-cylinder engines: to remove maple a belt, to take out the tension device (Generator).
  9. To remove a protective casing of a gear belt (head Engines). The gear belt remains established.
  10. To remove a hose of system of the cooling, conducting to a radiator and located below on a branch pipe of the case of the thermostat.
  11. To turn off two bolts on a cover of the case of the thermostat.
  12. Carefully to lift a gear belt through a partition on the thermostat case, to remove the thermostat case.
  13. To take out the thermostat.
  14. All models: at installation of the new thermostat its smaller condensing plate should show towards the engine.
  15. Only models with the 6-cylinder engine: the air valve on an external ring of the thermostat should show up.
  16. To replace laying.
  17. To tighten bolts on the case of the thermostat or the water pump the moment of 10 N • m.

Thermostat check

With the thermometer for jam making you can define, whether the regulator of cooling liquid opens at the ordered temperature.

 Opening beginning
Completion of opening
Lifting height
approximately 87°С
approximately 102°С
7 — 8 mm


  1. To remove the thermostat.
  2. To hang up the thermostat in a pan with water and to warm up water.
  3. To check, whether the plate of the valve rises at 87°С from a saddle.
  4. At this experience it is completely impossible to reach completion of opening (in an open pan water boils, as we know, at 100°С), but at least it is possible to see, whether the thermostat opens further.
  5. The full height of lifting is almost reached by that. That it is possible to see, it is enough to draw a conclusion on serviceability or malfunctions of the thermostat.