How to Repair a Radiator Thermostat

Lead Image
  • 1-2 hours
  • Beginner
  • 15-50
What You'll Need
Radiator thermostat
Radiator coolant
Gasket glue
Putty knife

Here are the tools, materials and steps that you need to follow to repair your car radiator thermostat. This repair will involve locating the old thermostat, removing it from the car and replacing it with a new radiator thermostat. The radiator thermostat controls the temperature of the engine. This is a vital function to keep you car from running hot and overheating. If you car overheats it may result in engine damage that could cost you several thousand dollars or the purchase of a new engine.

There is no “repairing” a broken car radiator thermostat. If it is no longer doing its job and keeping your radiator from running hot, it needs to be replaced with a new thermostat. If you want to do this by yourself and not take the car to a mechanic or certified technician, this article may help you accomplish this task.

Step 1: Purchase Parts for Thermostat Replacement

Purchase a new thermostat for your car, along with radiator coolant and gasket glue. The gasket glue is needed to affix the thermostat gasket to keep it from leaking. Be sure to know the vehicle make, year and model that you are attempting this repair on, including the engine type. This information is needed in order to match the correct radiator thermostat for your car.

Step 2: Remove Old Thermostat

Place a bucket underneath the radiator where the drain plug is located. Use a ratchet to loosen the drain plug and drain the coolant out of the radiator. The coolant needs to be disposed of in accordance to the environmental disposal methods for your community. You will replace the coolant with the fresh coolant that you purchased at the auto parts supply store.

Find the housing that holds the thermostat in place. Remove the bolts using the ratchet by loosening several bolts before completely removing one to prevent breaking or cracking the housing. Remove the housing and wipe the thermostat opening with a rag to remove any loose gasket pieces or debris that may fall into the engine. Take the old thermostat out, noting the direction in which it is facing.

Step 3: Remove the Old Gasket and Replace Thermostat

Use a putty knife to scrape the area where the gasket seal goes. Take the gasket glue and applicator and spread the glue on the thermostat opening. Put the replacement thermostat in the same direction that the old thermostat laid. Gluel gasket onto face.Place the housing cover back over the radiator thermostat and screw the bolts back on. Once sealed, tighten the radiator drain plug.

Step 4: Refill the Radiator

Remove the radiator cap and put radiator coolant into the radiator. Replace the radiator cap and turn the car on to test the temperature, making sure that the replacement was done correctly.