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. 205 I (741A/C)
2. 205 � (741A/C)
3. XM (Y3)
4. XM Break (Y3)
5. XM Estate (Y3)
6. ZX (N2)
7. XANTIA (X1_, X2_)
8. 205 I Convertible (741B, 20D)
9. 205 � Convertible (741B, 20D)
10. 205 II (20A/C)
11. 205 Mk II (20A/C)
12. 309 I (10C, 10A)
13. 309 � (10C, 10A)
14. 309 II (3C, 3A)
15. 309 Mk II (3C, 3A)
16. 405 I (15B)
17. 405 I Saloon (15B)
18. 405 � (15B)
19. 405 I Break (15E)
20. 405 � Estate (15E)
21. See more in applications

The principle of the thermostat work

The classic FEBI BILSTEIN 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.