Thermostat, coolant - 821718 VALEO

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. 500 / 595 / 695 (312_)
2. 500 (312_)
3. PUNTO (199_)
4. DOBLO MPV (263_)
5. DOBLO Kombi (263_)
6. DOBLO Combi (263_)
7. DOBLO Cargo (263_)
8. BRAVO II (198_)
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10. MITO (955_)
11. GRANDE PUNTO (199_)
12. COMBO Box Body/MPV (X12)
13. COMBO Tour (X12)
14. LINEA (323_, 110_)
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16. DOBLO Platform/Chassis (263_)
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18. PUNTO EVO (199_)
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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.