Replacing a thermostat on a car is fairly easy and only takes about 45 minutes to an hour to do so. You know it's time to replace your thermostat when your car is permanently overheating or running at a higher temperature than normal. You need to check with your user manual for your car in order to find your thermostat before you begin replacing it. Not all thermostats are in the same place in every car.
Find and succeed the upper radiator hose to where it connects to the thermostat housing. Don't know what thermostat housing is? It's where the opposite end of the upper radiator hose mounts to the engine. Drain the coolant from your radiator until it is below the thermostat. If you do not drain the coolant, it will cause your antifreeze to leak on the ground. That is very risky to animals as well as small children. So take precautions and drain coolant.
You need to loosen the clamp and remove the radiator hose from the thermostat housing. Make sure you have towels or rags near by to catch the antifreeze that leaks when removing the radiator hose from the thermostat housing. You need to remove the thermostat housing from the engine. You must first remove the bolts that hold this housing in place. Once you have removed them, you should be able to pull the housing directly out of the engine.
After removing the housing, you then can remove the old thermostat. Make sure you take a note of the alignment for future reference. Have a rag in hand and place it in the thermostat's mounting hole so that no gasket material can enter the engine. After doing so, you can scrape the gasket from the housing and the engine.
Now that you have scraped the gasket, housing and engine, you can setup your new thermostat. Make sure you position it the same way as the old one. This is important; failure to do so may cause this thermostat to be ineffective. Reinstall the housing and make sure the bolts are locked in. Use your torque wrench to the specifications of the manufacturer. Do not over tighten them. Reinstall the radiator hose to thermostat housing and clamp.
You now need to refill the radiator with coolant and start your car. Allow your car to heat up to general temperature; while it is warming up, check for leaks. If you observe any, tighten any bolt as much as principal to stop the leak. You can now stop your car, and allow it to rest completely. Check your coolant level, and add more if needed.
How to Replace the Car Thermostat