How to Change the Thermostat in a Mitsubishi Galantby Contributor
If your Mitsubishi Galant is showing telltale signs of a faulty thermostat, such as running hot or the heater is no longer blowing warm air, you might want to tackle this procedure yourself. In less than an hour, you can have your Galant up and running at peak performance.
Raise the front of your Mitsubishi Galant with a jack and lower onto jack stands, or use wheel ramps. Disconnect the negative cable from the battery. Drain the coolant into a suitable container by opening the drain plug on the bottom of the radiator.
Follow the upper radiator hose to where it meets the engine at the thermostat housing. Loosen the clamp at the engine end of the radiator hose and pull the hose off the thermostat housing.
Remove the two bolts on the thermostat housing cover and pull off the cover. Note the position of the old thermostat and remove it from the thermostat housing. Place a rag in the thermostat housing and scrape any gasket residue from the inside of the thermostat housing cover.
Take out the rag and insert the new thermostat in the same position as the old one, with the spring-side facing into the engine. Install the new gasket or o-ring, depending on the type of thermostat you are installing. Note that most late 1980s and early 1990s Galant models use a thermostat gasket.
Replace the thermostat housing cover and tighten the bolts. Reattach the radiator hose and tighten the clamp. Fill the radiator with new coolant, or use the coolant drained from your Galant earlier if it's relatively new and clean.
Start your Mitsubishi Galant and run with the heater on high until it reaches operating temperature. Make sure the heater is blowing warm air to ensure the thermostat is working properly. Check for leaks and tighten the radiator hose clamps if you detect any.
- Torque the thermostat housing bolts on your Mitsubishi Galant in accordance with your engine size following manufacturer specifications found in your owner's manual.
- Don't drain coolant from your Galant while the engine is hot.