Thermostat — removal, inspection and installation

Thermostat

OHV engine thermostat

The cooling system thermostat speeds up the engine warm-up and maintains the required thermal conditions. The thermostat, depending on the temperature of the coolant, automatically turns on or off the radiator of the cooling system, passing liquid through the radiator or bypassing it.

In the event of a thermostat failure, the engine either does not warm up completely, or overheats, but the radiator remains cold.

Withdrawal

1. Disconnect the ground wire and drain the coolant.

2. Remove the cooling and heating hoses from the thermostat and disconnect the temperature sensor connector.




3. Remove thermostat housing from cylinder head (thermostat mounting bolts are indicated by arrows).

4. Remove the retaining ring and remove the thermostat from the housing.

5. Checking the thermostat.

6. Place the thermostat in a vessel of water and heat it slowly, watching the thermostat open.

7. At a temperature of 89–93°C, the thermostat opens. The thermostat reaches full opening at 99-102°C; tolerance:±3°C.

8. Installation is made in sequence, return to removal. Be sure to use a new O-ring and check the cooling system for leaks.