Checking and repairing the thermostat

At the thermostat, the temperature of the beginning of the opening of the main valve and the stroke of the main valve are checked. The thermostat is installed on the stand BS-106-000 and lowered into a tank with technical glycerin. From the bottom to the main valve 4 (see fig. eleven) abut the indicator leg bracket. The initial temperature of glycerin in the tank should be 78-80°C. The temperature of glycerin is gradually increased by about 1°C in 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 valve opens. The thermostat must be replaced if the temperature at which the valve starts to open differs from (87±2) °C and the valve travel when the temperature rises to 102°C will be less than 8 mm.

The simplest check of the operation of the thermostat 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 arrow of the liquid temperature gauge does not reach 3-4 mm before the beginning of the red zone of the scale.