2. Disconnect the upper hose from the thermostat housing cover, unscrew the bolt, remove the cover (photo).
11.3. Remove the thermostat housing cover. When installing, check that the thermostat is positioned as shown
3. Throw away the gasket and remove the thermostat.
4. The thermostat can be easily checked. But note that if it stays open at room temperature, it is faulty and needs to be replaced.
5. Boil water and lower the thermostat on a rope into it (Pic. 2.12). Remove the thermostat from the water; it should close after a while. This is a basic check. You can check the correct opening temperature and maximum lift of the thermostat valve (see Specifications). Note that the opening temperature is imprinted on the body protrusion, on the outlet side (to the radiator). The thermostat should close when the temperature drops by 5°C from the nominal opening temperature.
Pic. 2.12. Thermostat test
6. If the thermostat does not open, or does not open completely within the specified temperature range (see Specifications) or if it does not close when removed from the water, it must be replaced.
7. When replacing a thermostat, make sure that the new thermostat will fit your vehicle, as thermostats are made to fit a variety of models and a wide range of temperatures.
8. Clean the surface of the thermostat housing and cover and install a new gasket.
9. Position the thermostat with the vent hole facing up.
10. Tighten the bolts to the torque specified in Specifications, install the upper hose, add coolant to the radiator and expansion tank (see Chapter 5).