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. E-CLASS (W124)
2. E-CLASS Saloon (W124)
3. 124 Saloon (W124)
4. S-CLASS (W126)
5. S-CLASS Saloon (W126)
6. SL (R107)
7. S-CLASS Coupe (C126)
8. SL (R129)
9. S-CLASS (W140)
10. S-CLASS Saloon (W140)
11. S-CLASS Coupe (C140)
12. CL-CLASS Coupe (C140)
13. G-CLASS (W463)
14. G-CLASS SUV (W463)
15. G-MODELL (W463)
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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.