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. BX (XB-_)
2. BX Break (XB-_)
3. C15 Van (VD_)
4. 205 II (20A/C)
5. 205 Mk II (20A/C)
6. 309 I (10C, 10A)
7. 309 � (10C, 10A)
8. 309 II (3C, 3A)
9. 309 Mk II (3C, 3A)
10. 405 I (15B)
11. 405 I Saloon (15B)
12. 405 � (15B)
13. 405 I Break (15E)
14. 405 � Estate (15E)
15. 200 Hatchback (XW)
16. 400 (XW)
17. 400 Tourer (XW)
18. C15 Estate
19. 205 Hatchback Van
20. 405 I Estate Van (15_)
21. See more in applications

The principle of the thermostat work

The classic VALEO 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.