Checking the Thermostat (VAZ-2101)

The thermostat must be checked for the temperature at which the main valve begins to open and the stroke of the main valve. To do this, lower the thermostat into a tank with water or coolant and secure it to the bracket. The indicator leg bracket rests against the main valve from below.

The initial temperature of the liquid in the tank should be 73-75°C. The temperature of the liquid is gradually increased, by about 1°C per 1 min with constant stirring, so that it is the same throughout the volume.

The temperature at which the main valve stroke is 0.1 mm is taken as the temperature at which the main valve begins to open. The thermostat must be replaced if the temperature at which the main valve begins to open is not within 81°C or if the valve stroke is less than 6.0 mm.

The simplest check can be done by touch directly in the car. After starting a cold engine with a working thermostat, the lower radiator tank should heat up when the liquid temperature indicator arrow is approximately 3-4 mm from the tap zone of the scale, which corresponds to 80-85°C.