Thermostat: 1 - inlet pipe (from the radiator); 2 - rubber insert; 3 – solid thermosensitive filler; 4 - bypass valve spring; 5 - inlet pipe (from the engine); 6 - bypass valve; 7 - outlet pipe (to the pump); 8 - main valve spring; 9 - main valve; 10 - branch pipe (from expansion tank); 11 - piston.
The need to replace the thermostat (see fig.) occurs when the temperature of the engine is unstable (engine overheating or insufficient heating).
To test the operation of the thermostat on a car, you must start the engine and put your hand on the lower radiator pipe - it must be cold. When the coolant temperature reaches 80–85°C, the hose should begin to heat up. If this does not happen, remove the thermostat and check its operation.
Warning! It is necessary to remove the thermostat only on a completely cooled engine.
Helpful advice. For convenience, remove the battery.
You will need a screwdriver.
1. Turn away a stopper of a broad tank.
2. Place a container under the drain hole, unscrew the radiator drain plug and drain the coolant from the radiator.
3. Loosen the clamps, disconnect the radiator outlet and inlet hoses from the thermostat housing.
4. Loosen the clamps, disconnect the hoses of the inlet pipe of the water pump and the inlet pipe from the thermostat and remove the thermostat.
5. Immerse the thermostat in water heated to 78–80°C. Heat the water, stirring constantly, until (87±2) °C.
6. At temperature (87±2) °C The main thermostat valve should begin to open. If it doesn't, replace the thermostat.
7. Install the thermostat in the reverse order of removal.
8. Fill the cooling system with liquid and check the cooling system for leaks.