How to Replace a Car Thermostat

  • 1-2 hours
  • Beginner
  • 15-30
What You'll Need
New thermostat
New gasket
Gasket sealant
Flathead screwdriver
Putty knife
Spray lubricant
Protective gloves
Disposable container

If you find that your car engine becomes excessively hot in a short period of time, the problem is likely to lie with the car thermostat. Having the ability to locate and replace the component will help you to resolve your overheating problems

Step 1 – Gain Access

The first step necessary to replace a car thermostat is to gain access to it. Lift the hood and ensure that it is secured so that there is no risk of it dropping and causing injury. This will enable you to locate the thermostat. While wearing a thick pair of gloves, put a rag over the radiator cap. You will then be in a position to slowly remove the cap while listening for the release of pressure. When the sound stops, you can remove the cap completely.

Step 2 – Remove Thermostat Hose

You will be able to identify the car thermostat by a short length of black hose that will be visible in the radiator, this will be attached to the cover of the thermostat. You will find that there is a bolt at either side of the cover and the hose is clamped into place. Depending on the manner in which the hose is attached, a screwdriver or pair of pliers can be used to remove the fasteners that hold it in place. The hose can then be twisted from its holding with the assistance of a screwdriver if it proves stiff. Have a container handy during this process to catch any coolant that will be released.

Step 3 – Remove Thermostat Cover

With the hose removed, you will be able to also remove the thermostat cover. Use a wrench to remove the two bolts that hold the cover in place. Lift the cover out of place after they have been removed and withdraw the thermostat along with it. Take note of the recess that the thermostat is removed from so that you know where the replacement should go. Use a putty knife to remove the existing gasket from the thermostat cover and a piece of sandpaper to ensure that there are no traces of it remaining and that the surfaces are clean and smooth.

Step 4 – Fit Thermostat

Fit the new car thermostat into place after ensuring that the spring mechanism is correctly in place. Apply some gasket sealant to the thermostat cover and the cover base, this will enable you to ensure that there will be no leaks when the system is sealed. Replace the gasket at this point and ensure that the holes for the bolts are properly aligned.

Step 5 – Close and Finish Up

Replace the thermostat cover along with the corresponding bolts to secure it. You will then be able to reverse the process to replace the radiator hose. Replace the depleted coolant if necessary. Do not start the car until the gasket sealant has dried, you will then be able to check whether the new car thermostat is operating correctly.