How to check serviceability of the thermostat

How to check serviceability of the thermostat

One of the devices which are responsible for maintenance of optimum temperature condition of work of DVS is the thermostat designed to direct the cooling liquid (CL) depending on temperature on small or on big contour of the cooling system. It is possible to check operability of the thermostat directly on the car and also having removed it. For check of operability of the thermostat on the car there are two ways.

It is required to you

  • - thermometer;
  • - cooling liquid.


1. Start the engine. Check to the touch condition of heating of the lower and top branch pipe. If in warm-up period of the engine temperature of the top branch pipe increases quicker, than lower - the thermostat is serviceable. If they heat up at the same time, the thermostat needs to be changed. It also is the first way which consists in check of temperature difference in the inlet and final branch pipes which are bringing and taking away cooling liquid to car radiator.

2. Open jellied mouth and make sure that the level of cooling liquid meets standard. Start the engine, lower the thermometer in jellied mouth (the device which is capable to take temperature more than 100 wasps is necessary). Under condition when indications of the thermometer at first remain invariable, and on reaching working temperature sharply increase, the thermostat is considered serviceable. Otherwise indications of the thermometer increase gradually, in process of warming up of the engine. It is the second way which is intended for cars which on radiator of cooling have jellied mouth.

3. Remove the thermostat from the car, the third option is intended for more exact check of operability of the thermostat. Check condition of adherence of the valve. The spring has to press it to the thermostat body densely.

4. Prepare the thermometer, with graduation of scale more than 100 wasps and the technology solution consisting of ethylene glycol and water in the ratio 50/50.

5. Place the thermostat and the thermometer in solution so that they did not concern bottom and walls of capacity. Heat solution in the course of what control its temperature. The beginning of valve actuation of the thermostat occurs at temperature of 87 wasps, and at achievement of 102 wasps the valve has to be open completely. If instead of technology solution normal water is used, these indicators are equal 83 wasps and 98 wasps respectively. In case of deviation from these values the thermostat is considered faulty.

Author: «MirrorInfo» Dream Team