Thermostat — Removal, Checking and Installation (Opel Ascona C)

1. Typical signs of a faulty thermostat include slow engine warm-up (longer than 7-8 minutes) or its overheating, which is indicated by boiling of the coolant or detonation of the engine after it is turned off.

2. Before removing the thermostat, some of the coolant should be drained (see section 3).

Engine 1.3

3. Loosen the mounting bolts and remove the camshaft belt cover. Disconnect the upper radiator hose from the engine - this is where the thermostat housing is located.

4. Unscrew the 2 mounting bolts and remove the housing to access the thermostat located in the cylinder head. Remove the thermostat, paying attention to how it was installed (see photos).







5. To check the operation of the thermostat, lower it on a thread into boiling water. When immersed in boiling water, the thermostat should open. Remove the thermostat and check if it closes. This is a fairly simple functional test that can help identify a faulty thermostat. Using a thermometer, you can check the opening temperature of the thermostat (see Specifications), however, you can no longer check the temperature of full opening, since it exceeds the boiling point of water. When replacing the thermostat, check that it matches the temperature characteristics of your model (see photo).



6. The thermostat is installed in the reverse order. Replace the thermostat sealing ring and reinstall it correctly (see photos).







7. Tighten the thermostat housing bolts to the required torque and add coolant to the system.

Engines 1.6 and 1.8

8. The procedure for removing, checking and installing the thermostat on these engines is basically similar to that given for the 1.3 engine, with the difference that the thermostat is located on the outside of the camshaft belt cover, and access to it is much easier (see photos).



9. On carburetor models, remove the air cleaner. Drain the coolant and remove the bolts securing the thermostat housing cover.

10. Remove the thermostat and check its operation if necessary (see paragraph 5).



11. When installing the thermostat, always replace the seal on its housing cover.

12. If it is necessary to remove the thermostat housing, first remove the camshaft timing belt and the rear belt shield (see chapter 1).

13. Disconnect all hoses from the thermostat housing, noting their relative position.

14. Unscrew the 2 bolts securing the thermostat housing and remove it. Remove the sealing ring.

15. Installation of the thermostat housing is carried out in the reverse order. Install a new O-ring and tighten the housing bolts to the specified torque.

16. Fill the cooling system with liquid (see section 6).