Removing
1. The thermostat is housed in a housing that bolts to the side of the water pump.
2. Disconnect the negative cable from the battery. Drain the cooling system as described in Chapter 1.
3. Loosen the clamp and disconnect the thermostat cover from the body (see fig. 4.3).
Pic. 4.3. Loosen the clamp and disconnect the coolant hose from the thermostat cover (4-cylinder petrol engine)
4. Turn away bolts of fastening and remove a cover of the thermostat from the case. If the lid is stuck, tap it gently or rock it back and forth. Do not use the lever so as not to damage the mating surfaces (see fig. 4.4).
Pic. 4.4. Remove the thermostat cover from the housing
5. Remove the seal, then lift the thermostat out of the housing, noting its orientation (see fig. 4.5, a, b).
Pic. 4.5, a. Remove seal...
Pic. 4.5b....then lift the thermostat out of the housing
Examination
6. For a rough test of the thermostat, hang it on a wire in a container of water. Heat the water to a boil - the thermostat should open. If it doesn't open, replace it.
7. Using a thermometer, it is possible to determine the lingering temperature of the thermostat opening. Compare with technical data. The opening temperature is also indicated on the thermostat.
8. A thermostat that does not close when the water cools should also be replaced.
Installation
9. Before installation, thoroughly clean the mating surfaces of the cover and body.
10. Install the thermostat into the housing, keeping the spring-loaded side facing towards the housing. Recall that on diesel engines, the recess on the thermostat rim must be aligned with the rib on the housing cover. On petrol models, install the thermostat so that the bleeder valve is at the highest point in the housing.
11. Fit the new seal into the housing, making sure it is properly seated.
12. Establish a cover of the case of the thermostat, then establish bolts of fastening and tighten them with demanded effort.
13. Connect the cooling hose to the thermostat cover.
14. Fill the cooling system as described in Chapter 1.