Thermostat gasket: common defects and their signs

1. Wear and elasticity loss.
   • Leakage of cooling liquid out of the thermostat mounting location.
   • Increased antifreeze consumption.
   • Increased engine temperature.
2. Thermal and mechanical damages.
   • Air locks in the cooling system.
   • Engine overheating.
   • Pinkish traces of anti-freeze on engine elements.

How to replace thermostat gasket?

The thermostat gasket is an expendable spare part which cannot be repaired, just like other parts which assure protection and hermeticity of car system elements, for example, the injection nozzle gasket, the differential gasket, etc. The thermostat gasket should be replaced if defects are found.

Possibility of unsupervised replacement depends on construction of the cooling system and mounting location of the thermostat. If it is located directly near the water pump, replacement procedure will be more complicated, special tools and skills will be necessary. In this case you should apply to a service station.

If the thermostat is mounted near the cylinder head block outlet, the sealing element can be replaced single-handedly. Action sequence may be slightly different for various car models, but generally, to replace the component you need:

1. Drain cooling liquid into a reservoir.
2. Unscrew the nuts fastening the thermostat housing cover.
3. Remove the housing cover. Take out the defective sealing ring.
4. Install a new ring.
5. Install the housing cover in place, treating it with sealing compound and tightening the fasteners.
6. Fill cooling liquid.
7. Start the engine and make sure there is no antifreeze leakage.

Replacement of the sealing elements located in the engine parts and auxiliary equipment of the vehicle, such as the thermostat gasket, the oil filter housing gasket or the gearbox gasket is performed only after cooldown of the engine.