Keeping your Kia running cool is as simple as making sure the engine thermostat is properly working. If you've noticed that the cabin inside of your Kia will not properly heat up, your thermostat may be stuck in the open position, letting too much antifreeze into the engine. If you're Kia has been overheating, the thermostat is most likely stuck in the closed position. This prevents fluid from running through the engine. Both situations can be costly if not attended to.
Open the engine bay bonnet on your Kia and locate the radiator hose that is connected to the top of the radiator. The other end of the radiator hose connects to the thermostat housing. Using a screwdriver, remove the clamp that holds the radiator hose onto the thermostat housing. It is possible that some radiator fluid will run out of the housing and/or the hose. This is normal and very little should leak out.
Remove the thermostat housing by removing the bolts that hold it into place. Depending on the engine that is in your Kia you may need to use an ratchet extension bar (often called a breaker bar) to access the bolts. Once the bolts are removed you can lift the thermostat housing off of the thermostat.
Pull the thermostat out of the intake manifold and replace it with a new one. Make sure you put the new one in with the correct side up. This will ensure the thermostat works correctly.
Pull the old thermostat housing gasket off of the intake manifold. You may need a scraper to remove. This depends on the age of the vehicle. If the vehicle is older, the gasket has likely become soft and may stick to the manifold. All of the old gasket must be removed to prevent leaking. Once the gasket is removed, replace it with a new one.
Bolt the thermostat housing back into place and reconnect the radiator hose. Turn the Kia on and allow it to run until the engine has heated up. Check the base of the thermostat housing for any leaks in the gasket. If it does leak, tighten the thermostat housing bolts tighter.