Changing a Car Thermostat

Changing a car thermostat can keep you from being stranded by the side of the road while your car does its imitation of Old Faithful-spewing steam and coolant all over. Luckily, your car's thermostat is inexpensive and easy to change out.

Changing A Car Thermostat Is Simple

If you can turn a wrench, you should be able to change a car thermostat. The thermostat is typically found under a metal housing on the top of your engine. The housing is located at the engine end of the radiator hose coming from the top of your radiator. Here's how to get started:

• That's cold. Make sure to allow your car's engine to cool completely before starting. A warm engine will put a lot of pressure on the cooling system. Opening a hot radiator is a recipe for disaster and a painful mistake you'll only make once.
• Drainage. With a catch pan under your radiator, open the valve at the bottom of the radiator and drain as much coolant as you can from the engine.
• Locating your thermostat. Your thermostat will be under a housing connected to the top radiator hose running from the radiator to the engine. If you have trouble locating the thermostat housing, check you vehicle's repair manual.
• Unhook the hose. With a catch pan on the ground under the thermostat housing, unhook the clamps holding the radiator hose to the housing. Be aware that a significant amount of coolant will spill from the hose when it is loosened.
• Remove the housing. Remove the thermostat housing by loosening the bolts holding it to the engine block. An appropriately sized socket wrench with an extension will make this job easier.
• Out with the old. Take note of the position and orientation of the thermostat when the housing is removed. Pull the thermostat from its position under the thermostat housing and place it aside.
• The last gasket. Use a paint scraper to remove the remains of the old gasket from the base of the housing and from the engine area around the thermostat. Use steel wool to remove any leftover gasket or adhesive-you want shiny metal at this stage.
• A new start. Drop the new thermostat into place, making sure it matches the position and orientation of the old unit. Make sure the new thermostat sits flush into position.
• Getting a good seal. Affix the gasket to the thermostat housing with sealant, making sure the bolt holes line up correctly.
• Button up. Replace the thermostat housing and tighten down the bolts holding the housing in place. Attach the radiator hose to the housing and tighten the clamps completely.
• Getting cool. Close the valve at the bottom of the radiator and fill the radiator with coolant, following the owner's manual directions for your car. Start the car with the radiator cap off and carefully note the level of the coolant within the radiator. Add extra coolant if needed and then screw the radiator cap back in place.