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. 200 Hatchback (XW)
2. 400 (XW)
3. 100 / METRO Hatchback (XP)
4. POLO (6N1)
5. IBIZA II (6K1)
6. IBIZA Mk II (6K1)
7. Q5 (8RB)
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9. POLO (6R1, 6C1)
10. POLO (6R1, 6C1, 601, 603)
11. A2 (8Z0)
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13. 100 Convertible (XP)
14. POLO (6N2)
15. POLO CLASSIC (6V2)
16. FLIGHT CLASSIC (6V2)
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18. POLO Variant (6V5)
19. POLO Estate (6V5)
20. FABIA I Combi (6Y5)
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The principle of the thermostat work

The classic HOFFER 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.