5.2.4. Check of the thermostat

Check without removal of the thermostat


  1. Before removing and checking operability of the thermostat, make sure that problems with cooling of the engine arose not owing to falling of level of the heat carrier, or weakening of a belt of the GRM drive. Check serviceability of functioning of the indicator for combinations of devices.
  2. If the engine insufficiently quickly gets warm up to the working temperature (according to indications of the indicator), it is necessary to remove the thermostat (see the Section Removal and installation of the thermostat) and to check whether it is jammed in open situation, - in case of need make replacement.
  3. Also the option is not excluded that the thermostat just was not installed during performance of the last service of the car. Operation of the car at the removed thermostat is characterized by the increased fuel consumption and excessive concentration of toxic components in the fulfilled gases.
  4. At an overheat of the engine feel the top hose of a radiator, - if the hose is not heated-up, therefore the thermostat is jammed in a closed position and the heat carrier continues to circulate on a small circle, without getting to a radiator. Replace the thermostat. Otherwise it is necessary to consider the other possible causes of an overheat of the engine (see the Section Diagnostics of Malfunctions in the Head Vvedeniye at the beginning of the Management).

Check with removal of the thermostat


  1. Remove the thermostat (see the Section Removal and installation of the thermostat).
  1. Lower the thermostat on a piece of a twine in the capacity filled with water, - the thermostat should not concern capacity walls.
  1. Lower the thermometer in water and begin to heat capacity, watching behavior of the main and additional valves of the thermostat. Compare results of measurement to requirements of Specifications of the Head of the Cooling system, heating, ventilation and air conditioning.
  1. Take the thermostat and let's it cool down, - valves have to be closed completely.
  2. The faulty thermostat is subject to replacement.