How To Replace A Chevy Blazer Thermostat

Changing the thermostat on your Blazer may seem intimidating; however, with basic mechanical skills and hand tools, you can save yourself a ton of cash by changing your Blazer’s thermostat in your own garage.

What You’ll Need:

  • OEM replacement thermostat and gasket
  • Socket wrench and socket set
  • 10” socket wrench extension
  • Gasket scraper
  • Drain bucket
  • 2 gallons of coolant

Step 1.

With your Blazer parked on a flat surface, lift the hood, and slowly remove the radiator cap.

Step 2.

With the drain pan in place under the radiator, drain the coolant from the radiator — retighten when completely emptied.

Step 3.

Locate the thermostat and remove the plastic heater hose clip from the lower part of the thermostat. Remove bolts from the thermostat using the socket wrench, extension, and socket. The thermostat can now be pulled from the engine.

Step 4.

Clean the flange of the housing with the gasket scraper. Install new gasket and thermostat and replace bolts. Reinstall the heater hose clip.

Step 5.

Refill the system with coolant/anti-freeze and you’re ready to go! Note that it will take quite a while to properly refill the system as bubbles will trick you into thinking the system is full.

Only use genuine GM replacement parts when replacing the thermostat to restore full function and prevent premature wear and failure of other parts. Also, keep an eye on the engine temperature for a few days to make sure you put enough coolant back into the system.