Thermostat is a device for maintaining a static (constant) temperature, as its name implies. There are thermostats of different designs in many devices and mechanisms, from water heaters to refrigerators. There is also a thermostat in a car's internal combustion engine (liquid-cooled, of course). In a car, the thermostat regulates the temperature of the coolant (antifreeze): it accelerates the warm-up of a cold engine and provides heat removal from the hot one. Therefore, the engine works more efficiently and more comfortably for the driver, especially in winter - without a thermostat, the stove would usually blew cold air.

1. A6 (4G2, 4GC, C7)
2. A6 / S6 (4G2, 4GC, C7)
3. A7 Sportback (4GA, 4GF)
4. A7 / S7 Sportback (4GA, 4GF)
5. A6 Avant (4G5, 4GD, C7)
6. A6 (4F2, C6)
7. A6 Saloon (4F2, C6)
8. A6 / S6 (4F2, C6)
9. A4 (8EC, B7)
10. A4 Saloon (8EC, B7)
11. A4 / S4 (8EC, B7)
12. A4 Avant (8ED, B7)
13. A4 / S4 Avant (8ED, B7)
14. A6 Avant (4F5, C6)
15. A8 (4E2, 4E8)
16. A8 Saloon (4E2, 4E8)
17. A8 / S8 (4E2, 4E8)
18. A8L (4E2, 4E8)
19. A5 (8T3)
20. A5 / S5 (8T3)
21. See more in applications

The principle of the thermostat work

The classic TOPRAN brand Thermostat, coolant is a movable valve that moves due to a change in the external environment - heating or cooling of antifreeze. The thermostat is made of a thermoelement filled with a substance resembling wax in structure - ceresin, with the addition of copper powder, graphite or aluminum for better thermal conductivity. At a certain temperature of the antifreeze, ceresin expands, opening the thermostat valve. When the motor cools down, ceresin contracts and the thermostat closes again.