Checking and replacing the thermostat

If a defective thermostat gets stuck in the closed position, it will cause the engine to overheat; if the thermostat is constantly open, the engine will warm up for an excessively long time. The thermostat cannot be repaired; in case of a defect, it must be replaced. Make sure the new thermostat is properly labeled, which is usually found on the base of the thermostat.

Remember that from August 1978 thermostats with a higher opening temperature are installed than on previous engines.

Thermostat Replacement - 1.1 / 1.3L Engines

The thermostat is located in the water outlet at the rear end of the cylinder head.

Disconnect the lower radiator hose and drain the cooling system until the level is below the thermostat.

Disconnect the upper hose from the cylinder head. Loosen the thermostat hose bolts and remove the thermostat (pic. E:5).



Clean the thermostat housing in the housing and install a new thermostat. It is important to set the thermostat to the correct position - if the thermostat is set incorrectly, the engine will overheat. Install the thermostat hose with a new O-ring.


Fasten the hoses and add coolant to the system.

Start the engine, warm it up to operating temperature and check the operation of the thermostat. Check the system for leaks Check the coolant level again with a cold engine.

Replacement - engines 1.5 / 1.6 / 1.8 l

Replace thermostat", as described above. The thermostat is located under the bottom pipe of the cooling pump (pic E:4).



When replacing the thermostat, install a new fitting O-ring. Make sure the thermostat is in the correct position during installation.

Thermostat check

If in doubt about the thermostat's performance, remove it from the engine. The operation of the thermostat can be checked (thermostat opening temperature see section "Technical data").

If the thermostat, removed from a cold engine, is open at room temperature, then it is defective - replace it.

1. If the thermostat is closed, hang it in a glass filled with water so that it does not touch the walls and bottom (pic. E:6).



2. Gradually heat the water, checking its temperature with an accurate thermometer.

3. If the thermostat does not open when the required temperature is reached, does not open completely or does not open at all, replace it.