Thermostat
Hint: If the engine boils on the road due to a faulty thermostat, either a tow truck or removing the thermostat on site can help. If you decide to remove the thermostat, then you must wait until the temperature of the coolant drops. At this time, you can get containers for draining the coolant.
Removing the thermostat
Removing a stuck thermostat on the road is a rather problematic task. It is located quite deep at the bottom, so almost all the coolant will have to be drained. In addition, with a hot engine, you will have to wait a long time before you can start working without fear of scalding your hands. When installing a new thermostat, it is necessary on the thermostat housing or water pump.
4-cylinder engine: In the illustration, the water pump and thermostat housing are shown in section so that you can see inside. The impeller is clearly visible (1) water pump. Near the thermostat (2).
After removing the housing cover (3) on the left side of the engine, the 5-cylinder engine has access to the thermostat (2). Position (1) shows the water pump.
Drain the coolant completely.
Models with 4-cylinder engines: remove the lower protection of the engine compartment (chapter «Body elements»).
Remove the hose at the bottom of the water pump housing (has already been done to drain the coolant).
Unscrew the two screws on the cover at the bottom of the thermostat housing.
Remove cover and thermostat.
Models with 5-cylinder engines: unscrew the two bolts on the cover of the thermostat housing.
Push the cover to the side and remove the thermostat.
Models with 6-cylinder engines: remove the V-belt, remove the tensioner (chapter «Generator»).
Remove toothed belt guard (chapter «Engines»). The timing belt itself remains installed.
Remove the coolant hose leading to the radiator and located at the bottom of the thermostat housing pipe.
Loosen the two screws on the thermostat housing cover.
Carefully lift the toothed belt through the baffle on the thermostat housing, remove the thermostat housing.
Take out the thermostat.
All Models: When installing a new thermostat, its smaller sealing plate must point towards the engine.
6-cylinder models only: air valve on thermostat outer ring must point up.
Replace gasket.
Tighten bolts on thermostat housing or water pump to 10 Nm.
Thermostat check
With a jam thermometer, you can determine for yourself whether the coolant regulator opens at the prescribed temperature.
Remove thermostat.
Hang the thermostat in a pot of water and heat the water.
Check if the valve disc lifts off the seat at 87°C.
The completion of the opening with this experience is completely impossible to achieve (Water boils in an open pot at 100°C), but at least you can see if the thermostat opens further.
The full lifting height is thus almost reached. What can be seen is enough to conclude that the thermostat is working or not.
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