2.14.5. Thermostat

Fig. 2.78. Thermostat: 1 – perepuskny valve; 2 – an output branch pipe (to the pump); 3 – spring of the main valve; 4 – main valve; 5 – holder of the piston; 6 – piston; 7 – an entrance branch pipe (from a radiator); 8 – rubber insert; 9 – firm thermosensitive filler; 10 – spring of the perepuskny valve; 11 – an entrance branch pipe (from the engine)

At the thermostat it is necessary to check temperature of the beginning of opening of the main valve and a valve stroke. Install the thermostat at the stand and lower in a tank with technical glycerin. Rest the arm rychazhok connected with an indicator leg against the main valve 4 (fig. 2.78).
Reference temperature of liquid in a tank has to be 78–80 °C. Gradually increase liquid temperature approximately by 1 °C a minute at continuous hashing that it in all volume of glycerin was identical.
That at which the course of the main valve will make 0,1 mm is accepted to temperature of the beginning of opening of the valve.
The thermostat needs to be replaced if temperature of the beginning of opening of the main valve does not correspond (85 ±2) to °C or in case at achievement of temperature to 102 °C there is no contact of the valve of 1 saddle of a branch pipe 11. The simplest check of serviceability of the thermostat can be carried out to the touch directly on the car. After start of the cold engine at the serviceable thermostat the lower branch pipe of a radiator has to heat up when temperature of cooling liquid reaches 85–92 °C.