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. GOLF V (1K1)
2. RABBIT V (1K1)
3. TOURAN (1T1, 1T2)
4. ALTEA (5P1)
5. A3 Sportback (8PA)
6. OCTAVIA II Combi (1Z5)
7. PASSAT (3C2)
8. PASSAT Saloon (3C2)
9. PASSAT / Magotan (3C2)
10. JETTA III (1K2)
11. JETTA I Saloon (1K2)
12. JETTA V (1K2)
13. BORA V (1K2)
14. VENTO III (1K2)
15. PASSAT Variant (3C5)
16. PASSAT Estate (3C5)
17. See more in applications

The principle of the thermostat work

The classic MAHLE ORIGINAL 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.