How to Change the Thermostat in a Honda Preludeby Contributor
Though not manufactured since early in the new millennium, you may still be driving a Prelude, the sports coupe Honda produced between 1978 and 2001. If you've noticed a heating problem or your Prelude is overheating, you may need to change the thermostat.
Raise the front of your Honda Prelude with a jack and lower it onto jack stands, or use wheel ramps. Loosen the drain plug located at the bottom middle of the radiator. Drain the coolant into a suitable container. Reuse this coolant if relatively new and clean.
Twist slightly and pull the intake air duct from the air cleaner on top of the engine. Disconnect the two halves of the duct where it meets in front of the thermostat housing and remove that section of the duct.
Follow the upper radiator hose to where it meets the thermostat housing. Loosen the clip holding the hose to the housing and pull off the end of the hose from the thermostat housing. Take out the two bolts holding the thermostat housing cover. Note the position of the old thermostat and remove it. Install the new thermostat in exactly the same position, spring-side facing the engine.
Clean any residue from the old gasket off the inside of the housing cover. Install the new gasket. Apply a silicone sealer around the thermostat prior to installing, if desired.
Reinstall the thermostat housing cover, upper radiator hose and air duct. Fill the radiator with reserved or new coolant. Use a wrench to open the bleeder bolt located near the thermostat housing. Fill the radiator and tighten the bleeder bolt when you see coolant begin to spill from the bleeder.
Start your Honda Prelude and run with the heater blowing on high until the engine warms up. Feel the upper radiator hose to ensure it is getting hot. Check for leaks where the radiator hose meets the thermostat housing. Tighten the clamp holding the hose to the thermostat housing to stop any leaks.
- Use pliers to wrench the end of the upper radiator hose off the thermostat housing, if necessary. If replacing this hose, make a cut at that end of the hose to make removal easier.
- Do not drain coolant from your Honda Prelude if the engine is hot.
- Do not leave your Prelude on a jack while you drain the coolant and change the thermostat, as the car can easily slip. Use jack stands or wheel ramps.