Checking and repairing the thermostat (VAZ-1111)

The thermostat is checked for the temperature at which the main valve begins to open and the stroke of the main valve. The thermostat is installed on the BS-106-000 stand and lowered into a tank with technical glycerin. From below into the main valve 4 (see figure 11) rest the bracket against the indicator leg. The initial temperature of the glycerin in the tank should be 78-80°C. The temperature of the glycerin is gradually increased by approximately 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 valve opening start temperature. The thermostat must be replaced if the valve opening start temperature differs from (87±2)°C and the valve stroke is less than 8 mm when the temperature increases to 102°C.

The simplest check of the thermostat operation can be carried out by touch directly on the car. After starting a cold engine with a working thermostat, the radiator outlet pipe should heat up when the coolant temperature reaches 87-92°C, and the liquid temperature indicator arrow does not reach 3-4 mm before the beginning of the red zone of the scale.