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. 21 Saloon (L48_)
2. AX (ZA-_)
3. BX (XB-_)
4. BX Break (XB-_)
5. C15 Van (VD_)
6. XM (Y3)
7. XM Break (Y3)
8. XM Estate (Y3)
9. ZX (N2)
10. XANTIA (X1_, X2_)
11. 104
12. 104 Coupe
13. 205 II (20A/C)
14. 205 Mk II (20A/C)
15. 205 I Convertible (741B, 20D)
16. 205 � Convertible (741B, 20D)
17. 205 I (741A/C)
18. 205 � (741A/C)
19. 309 I (10C, 10A)
20. 309 � (10C, 10A)
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The principle of the thermostat work

The classic BorgWarner (Wahler) 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.