To ensure rapid heating and temperature control, the thermostat partially or completely cuts off the flow of coolant circulation through the radiator.
After the engine warms up, the thermostat opens. This allows the coolant to pass through the radiator and give off heat to the surrounding area.
The elastic ball in the thermostat is hermetically sealed in a metal case. It expands when heated and contracts when cooled.
Thermostat check
1. Remove the thermostat.
2. Make sure that when the thermostat housing is fully closed, the valve spring is tightly compressed. If the spring is not compressed tightly, replace the thermostat.
3. Hold the thermostat and thermometer in a container of 50/50 ethylene glycol and water. Do not let the thermostat and thermometer lie on the bottom of the container, as uneven heat distribution across the bottom can cause inaccurate temperature readings.
4. Heat the solution.
5. During the heating process, control the temperature of the solution.
The thermostat should start opening at 87°C and should open fully at 102°C.
If it does not open at these temperatures, replace the thermostat.
Withdrawal
Attention: before removing the cap of the expansion tank, wait until the engine has cooled down to prevent the emission of hot liquid or steam.
1. Drain the coolant.
2. Remove the rear of the timing case.
3. Loosen the hose clamp on the upper radiator hose on the thermostat housing.
4. Disconnect the top hose from the radiator.
5. Remove the screws securing the thermostat housing to the cylinder head.
6. Remove the thermostat housing from the cylinder head.
7. Remove the thermostat from the seat in the cylinder head.
8. Inspect the valve seat for foreign objects that may have caused the valve to close loosely.
9. Check that the thermostat is working properly.
10. Clean the thermostat housing and mating surfaces of the cylinder head.
Installation
1. Install the thermostat in the seat.
2. Install the thermostat housing.
3. Fix the thermostat housing, tighten the fixing screws to 20 Nm.
4. Install the removed elements in the reverse order of removal.