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. 200 Hatchback (XW)
2. 200 Convertible (XW)
3. 400 (XW)
4. 100 / METRO Hatchback (XP)
5. 100 Convertible (XP)
6. 200 Hatchback (RF)
7. A3 (8L1)
8. A3 / S3 (8L1)
9. PASSAT Variant (3C5)
10. PASSAT Estate (3C5)
11. OCTAVIA II Combi (1Z5)
12. TIGUAN (5N_)
13. TIGUAN/TIGUAN LIMITED SUV (5N_)
14. SCIROCCO (137, 138)
15. PASSAT CC (357)
16. CC (357)
17. PASSAT CC SEDAN GRANDE (357)
18. A3 (8P1)
19. A3 / S3 (8P1)
20. TOURAN (1T1, 1T2)
21. See more in applications

The principle of the thermostat work

The classic MAGNETI MARELLI 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.