Thermostat mounting elements
1 - gasket; 2 - inlet pipe for coolant assembled with thermostat; 3 - from the radiator; 4 - from the oil radiator.
As the engine heats up, the thermostat opens the circulation of coolant through the radiator. A thermostat that does not open in time causes the engine to overheat. This is indicated by the temperature gauge needle on the instrument panel rising when the radiator remains cold. A damaged thermostat may also remain open after the fluid has cooled. Then the engine does not reach normal operating temperature, and heating in winter is ineffective.
Caution: If the engine overheats after a short trip, the cause may be a clogged radiator, or a faulty fan or belt.
The thermostat is located in the housing.
Removal
- Remove the lower engine cover.
- Drain the coolant until the fluid level is below the thermostat housing.
- Remove the radiator expansion tank and slide the IPDM E/R module out (electrical installation block in the engine compartment) to the side.
- Unscrew the drain plug on the side of the cylinder block where the water pump is located.
- Disconnect the lower radiator hose and the oil cooler hose.
- Remove the coolant inlet pipe assembly with the thermostat (arrow).
- Do not disassemble the inlet pipe assembly with the thermostat. If necessary, replace the entire assembly.
- Clean the adjacent surfaces from any remaining sealant.
Examination
- Check the thermostat for corrosion.
- Measure and record the thermostat's dimension "a" (see picture on next page).
- Heat the thermostat slowly by suspending it in a container of water. In this case, the thermostat should not touch the walls of the container. At the same time, monitor the temperature with a thermometer.
- At the opening temperature, the thermostat should begin to open the valves.
Attention: The opening temperature is stamped on the thermostat.
- Continue heating the water until the temperature reaches the end of the opening. After removing the thermostat, measure dimension "b" and compare it to dimension "a." The difference should be 8.6 mm; otherwise, replace the thermostat.
| Thermostat | Opening begins | End of opening |
| Temperature,°C (degrees) | 82°C | 95°C |
- Check the thermostat for complete closing when the coolant temperature is 5°C below the opening temperature, the thermostat should close. Otherwise, replace the thermostat.
Please note: Even though the thermostats may be similar in appearance, the opening temperature may differ. Therefore, when replacing the thermostat, look at its markings.
Installation
- Installation is carried out in the reverse order of removal, taking into account the following:
- Install a new gasket.
- Tighten the thermostat housing mounting bolts to the block to a torque of 8.4-1 1.2 N·m.
- Fill with coolant.
- After installation, start the engine, let it run for a few minutes and check for coolant leaks.