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. GOLF VI (5K1)
2. SCIROCCO (137, 138)
3. A8 (4E2, 4E8)
4. A8 Saloon (4E2, 4E8)
5. A8 / S8 (4E2, 4E8)
6. A8L (4E2, 4E8)
7. GOLF V (1K1)
8. RABBIT V (1K1)
9. EOS (1F7, 1F8)
10. JETTA III (1K2)
11. JETTA I Saloon (1K2)
12. JETTA V (1K2)
13. BORA V (1K2)
14. VENTO III (1K2)
15. PASSAT (3C2)
16. PASSAT Saloon (3C2)
17. PASSAT / Magotan (3C2)
18. PASSAT Variant (3C5)
19. PASSAT Estate (3C5)
20. GOLF V Variant (1K5)
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.