How do I change the Thermostat on 205?

the thermostat is located on the cylinder head adjacent to the distribor you need to drain the coolant first then remove radiator top hose from the thermostat housing you may need to remove the air intake horn for better access undo the two bolts that hold the housing cover on you may have to give it tap with a plastic hammer but be gentle remove the thermostat if it is stuck dont lever out instead cut around it using a knive remove o,rings and replace them with new to fit the new thermostat its a reveral off the above