The thermostat in your Honda Accord helps the cooling system to maintain the engine operating temperature. A faulty (or sticking, as it is commonly referred to) thermostat can cause your Accord to overheat, potentially causing permanent engine damage. The 1998 Honda Accord was available with two different engines---a 2.3 L four-cylinder and a 3.0 L V6. Replacing the thermostat is essentially the same process on both engines.
Park your Accord on a flat surface. Concrete or asphalt is recommended. Pop your hood and disconnect the negative battery cable.
Let the engine cool for at least 30 minutes prior to beginning the procedure.
Locate the radiator drain plug underneath the front of the engine bay. Position a sealable container underneath it to let the engine coolant drain.
Use the flat head screwdriver to remove the drain plug. Let the coolant drain for 15 to 20 minutes, and then set the container aside.
Loosen the bolt around the upper radiator hose clamp where it connects to the engine. Remove the clamp, and then pull the hose away to expose the thermostat housing.
Remove the two (2) bolts from the thermostat housing, and then slide the housing off to expose the thermostat and gasket.
Pull the thermostat and gasket from the its mount and set them aside.
Attach the new thermostat gasket around the new thermostat. Apply a small amount of anti-seize lubricant around the thermostat threads.
Position the new thermostat in its mounting place, with the bleed hole pointing upward. Reattach the upper radiator hose and secure the clamp.
Turn the bleed valve near the thermostat housing 1/2 turn (for 2.3 L engines only).
Replace the radiator drain plug, and then refill the cooling system. Reconnect the negative battery cable, and then start the engine and check for leaks.
