How to Change a Grand Marquis Thermostat

by Gregory Crews

Replacing the thermostat in your Mercury Grand Marquis is a procedure that should take no more than half an hour to repair. The thermostat on the Grand Marquis does serve a unique function as well. The climate control system in the car will not operate efficiently as the car can not regulate cabin heat without a proper thermostat controlling coolant temperature. The thermostat balances the engine heat to send hot air through your heater and cooling down your motor to keep it from overheating.

Removing the Thermostat

Open the hood to locate the thermostat. The thermostat is situated at the motor end of the top radiator hose.

Unscrew the radiator hose with a flat head screwdriver. The hose should slide off the thermostat housing assembly.

Unbolt the cover of the housing assembly with a socket wrench. The cover should pop off once the two bolts are removed.

Pull the old thermostat out with your fingers. The thermostat is situated in the housing. You will need to remember how it is sitting in the assembly.

Scrape off the old gasket material from the housing assembly surface. Ensure the gasket is removed completely.

Installing the Thermostat

Place the new thermostat in the assembly. Ensure it is placed the same way as the old one was removed.

Place the gasket on the surface of the thermostat housing. You can put it on dry as it does not require any silicone. The gasket will help to seal the coolant system. Prevent it from leaking out.

Bolt the cover back on to the housing assembly. Ensure the cover is tightened snug. This will help to create a seal.

Place the hose back on to the assembly outlet pipe. Ensure you tighten the hose clamp till the hose is snug on the pipe.

Refill the radiator with coolant. You may have lost some in the replacement of the thermostat.

Tips

  • check If you are not able to replace your thermostat and still need to drive the vehicle. You can turn your heater on when the car starts overheating and this will help prevent the car from overheating.
  • check You can drain some of the coolant out of the system. Do this by placing a pan underneath the radiator. Loosen the petcock valve on the bottom of the radiator. Be sure to close the petcock valve when you are done draining the radiator.

Warning

  • close Give the Mercury time to cool down. You are working on coolant and when hot could cause serious injuries.

Items you will need

About the Author

Gregory Crews has been in the film industry for three years and has appeared in more than 38 major motion pictures and 16 television shows. He also writes detailed automotive tutorials. His expertise in the automotive industry has given him the skills to write detailed technical instructional articles.