To check the thermostat, start the engine on the car and touch the lower radiator hose with your hand - it should be cold. After the coolant temperature reaches 85-92°C, the lower radiator hose should begin to heat up. If this does not happen, remove the thermostat and check its operation.
To remove and install the thermostat on a car, you will need: a hex wrench «by 5», Phillips screwdriver.
1. Remove the plug from the expansion tank. Unscrew the drain plug at the bottom of the right radiator tank and drain the coolant from it (see «Coolant replacement»). Replace the drain plug on the radiator.
2. Loosen the two hose clamps securing the pipes to the thermostat covers and remove the thermostat cover pipes.
3. Turn out three bolts of fastening of a cover of the thermostat and remove it together with the thermostat.
Note. Pay attention to the condition of the sealing rubber ring in the groove of the thermostat socket. Replace a severely deformed, torn or loose sealing ring.
4. Overcoming the force of the spring, press the thermostat fixing plate down and, turning it in any direction, disengage from the grooves.
5. Remove the thermostat from the cover.
6. Before installing a new thermostat, test it by immersing it in water heated to 78-80°C. Heat the water, stirring constantly, to a temperature (87+2) °C.
7. At temperature (87±2) °С the thermostat rod should begin to move out of the power element. If it doesn't, replace the thermostat.
8. Establish on the car the thermostat in an order, the return to removal.
9. Fill the engine cooling system with coolant (see «Coolant replacement»). Replace the expansion tank cap, start the vehicle, check for coolant leaks from the thermostat hose connections, and let the engine idle to operating temperature to remove air pockets from the system.