The need to replace the thermostat may arise when the engine temperature is unstable: overheating or insufficient heating.
To check the thermostat on a car, start a cold engine and touch the upper radiator hose with your hand - it should be cold. After the coolant temperature reaches (105±1,5) °C, the hose should heat up quickly, indicating the start of fluid circulation in the large circuit. If this does not happen, remove the thermostat and check its operation.
1. Disconnect the wire from the terminal «minus» battery.
2. Drain the liquid from the engine cooling system (see «Coolant replacement»).
3. Squeeze the clamp of the thermostat heating element harness block...
4.... and disconnect the block.
5. Loosen the clamp of the radiator inlet hose, squeezing its bent ears with pliers, slide the clamp along the hose...
6.... and disconnect the hose from the thermostat fitting.
7. Turn out four bolts of fastening of the thermostat to a water distributor...
8.... and remove the thermostat.
9. Install the thermostat in the reverse order of removal.
NOTE: Pay attention to the condition of the thermostat o-ring. If it is severely compressed or torn, replace the ring with a new one.
10. Fill with coolant (see «Coolant replacement»).