Thermostat replacement
We remove the battery.
Drain the liquid from the engine cooling system (see Coolant replacement).
It is more convenient to remove the thermostat together with the upper hoses.
We loosen the tightening of the clamps and disconnect the upper thermostat hose from the pipe of the cylinder head...
...and the middle hose from the coolant pump nozzle.
Disconnect the lower hose either from the thermostat itself...
... or from the lower radiator pipe (see Engine Radiator Replacement).
We remove the thermostat.
Disconnect the hoses from the thermostat housing.
Thermostat check
To check the thermostat, lower it into a container with coolant. Lowering the thermometer there, heat the liquid to a boil. In the thermostat, the upper (bypass) valve and open bottom (basic) and remain in this position at a temperature of 82–87°C. As the liquid cools, the top valve should gradually open and the bottom valve should close.
Install the thermostat in the reverse order of removal.