Attention! All work should be performed only on a cold engine due to the risk of burns from coolant vapors.
The engine cooling system thermostat must be replaced in the following order. Remove the front auxiliary engine protection panel. Unscrew the coolant drain plug from the radiator. Drain the coolant and dispose of it. Unlock and disconnect the SS (1, Fig. 5.166) temperature sensor from the thermostat housing. Disconnect the cooling system pipe (2) and unscrew the nut (arrow).
Note: The thermostat is built into the cover and can only be replaced as an assembly.
Loosen the thermostat cover mounting bolts (3) and remove the cover together with the thermostat. Check the thermostat operation. Clean the mounting surfaces on the thermostat housing from dirt and traces of oil. Replace the sealing ring (1. Fig. 5.167).
Fill the engine cooling system, remove air from the cooling system (pump it up) and check the system for leaks. If there is a leak, slightly tighten the mounting bolts.
Check the operation of the viscous coupling (turning on the fan), has the temperature at the bottom of the radiator increased and is the thermostat housing sealed?.