Audi 100

1982-1990 of release

Repair and operation of the car

Audi 100
+ 1.1. Governing bodies and devices
+ 2. Technical characteristics
+ 3. Engines
- 4. Cooling system
   4.1. Replacement of cooling liquid
   4.2. Replacement and check of the thermostat
   4.3. Removal and installation of the water pump
   4.4. Check and replacement of the sensor of turning on of the electric fan
   4.5. Replacement of the sensor of temperature of cooling liquid
   4.6. Removal and installation of a radiator of the cooling system
+ 5. Exhaust system
+ 6. Power supply system
+ 7. Transmission
+ 8. Running gear
+ 9. Steering
+ 10. Brake system
+ 11. Body
+ 12. Electric equipment

4.2. Replacement and check of the thermostat


If the engine overheats, and the radiator thus remains cold, it indicates malfunction of the thermostat. If the faulty thermostat is constantly open, the engine will not get warm up to the working temperature. In these cases the thermostat is replaced.

1. To merge cooling liquid (see subitem 1-3 of subsection 4.1).
2. To turn off bolts and to uncover (5) (see rice. The cooling system of the four-cylinder engine) or (16) (see rice. Cooling system of the five-cylinder engine) thermostat.
3. To take out a sealing ring from a cover.
4. To take out the thermostat from a nest.
5. To measure a distance. Then to heat the thermostat in water. The beginning of opening of the thermostat of about 87 °C, the end of opening – about 102 °C. After heating to measure A distance. The serviceable thermostat a difference of distances of A and a has to have at least 8 mm.
6. To replace a sealing ring of a cover of the thermostat (see rice. Cooling system of the four-cylinder engine, rice. Cooling system of the five-cylinder engine).
7. To install the thermostat in a nest so that the arrow on a cross-piece of the thermostat was directed down.
8. To establish a cover, to twirl bolts and evenly to tighten the moment 10 N · m (1,0 kgfs · м).
9. To fill in liquid in the cooling system.