Removing and checking the thermostat (Focus Turnier 1)

Remove the thermostat only when the engine is cold. An experienced amateur can do this job, but a workshop will do it better. If you feel up to it, first release the operating pressure in the cooling system and have the necessary spare parts at hand. You need a thermostat, a thermostat housing cover gasket, and a long-lasting heat-resistant sealant (e.g. DP 300 from Wiirtli). Thoroughly renew the seals - the cooling system is constantly under pressure. Collect the leaking coolant in a clean container; after the repair, you can reuse it without hesitation. However, if you want to check the functionality of the old thermostat, heat water in an unnecessary pan and check the water temperature with a canning thermometer. You can read the regulation temperature on the thermostat housing and compare it with the water temperature. However, we do not advise you to rely on an untidy thermostat.

Stages of work

Open the expansion tank cap to relieve pressure in the cooling system. Be careful if the engine is hot: there is a risk of scalding



Place a clean container under the radiator, remove the lower radiator hose or unscrew the drain plug. Drain approximately three liters of coolant.

Loosen the hose clamp on the thermostat housing and remove the coolant hose.

Loosen the thermostat housing mounting bolts, carefully remove the housing, if necessary, help yourself a little with light blows (with a rubber or plastic hammer) on the housing.



Clean the sealing surfaces thoroughly, place the thermostat in the housing (the arrow on the housing points towards the radiator), lubricate the new gasket on both sides with a thin layer of sealant (e.g. DP 300) and fix it on the flange.

Carefully place the housing cover on top, apply a small amount of sealant between the cover and the threads, install and tighten the bolts evenly.

Secure the coolant hose, pour in the drained coolant, add more if necessary.

Warm up the engine at medium speed, constantly check all mounting points for leaks. Close the expansion tank.