An engine cooling system device designed to switch fluid circulation circuits - a thermostat. This element of the cooling system operates cyclically in closed and open mode.

1. 3 (E46)
2. 3 Saloon (E46)
3. 3 Coupe (E46)
4. 3 Touring (E46)
5. 3 Convertible (E46)
6. 3 Compact (E46)
7. See more in applications

At a low temperature of the coolant, the thermostat is closed, which contributes to its movement in a small circle and rapid heating to operating temperature. Upon reaching the nominal value, the thermostat opens and directs the coolant in a large circle through the radiator, where it is cooled. Thus, the constant opening and closing of the thermostat valve helps to maintain a constant temperature of the antifreeze in the system.

The construction of an BorgWarner (Wahler) brand Thermostat, oil cooling

The main elements of the thermostat:

1. frame;
2. stock;
3. thermoelement (usually artificial wax);
4. valve with piston and spring;
5. seals;
6. guiding device.

The thermostat can be framed or non-framed (mounted in the engine block). It has marking and embossed technical parameters (full opening temperature).