How to Change the Thermostat on a Toyota Paseo
Your Toyota Paseo requires the bleeding of the cooling system after changing the thermostat. It is a simple but necessary procedure to prevent engine overheating or damage. Learn how to replace the unit if you have a 1.5L (3E-E AND 5E-FE), 1.6L (4A-FE) or 1.8L (7A-FE) engine.
- Moderately Easy
- Drain pan
- Wrench set
- Ratchet and socket set
- Small piece of glass or mirror
- File or sandpaper if necessary
- New thermostat gasket and sealer
Open the hood. Make sure the engine is cool to the touch, and disconnect the black, negative battery cable. If your model is equipped with an air bag system, wait 90 seconds before starting to remove components.
Locate the thermostat housing by following the upper or lower radiator hose toward the engine. The hose connects to the housing fitting, which mounts to the engine with two nuts.
Remove the air intake duct if you have the 5E-FE engine. If your model comes equipped with a thermo switch, unplug the connector from the thermostat housing assembly.
Place a drain pan underneath the car in the direction of the thermostat housing, and remove the two mounting nuts using a wrench or ratchet and socket. Depending on your particular model, you might have to remove the hose from the thermostat housing first. Remove the clamp securing the hose to the thermostat assembly; then, carefully twist and pull the hose from its fitting.
Tap the thermostat housing lightly, using a rubber hammer to force it off the engine if necessary. Lift the thermostat housing off the engine and remove the thermostat from the engine.
Scrape old gasket material off the sealing surfaces from the thermostat housing and engine, if necessary, using a plastic scraper to avoid damage to the surfaces.
Place a small piece of glass or mirror against the sealing surface of the thermostat housing and check for wrapping. File or sand the sealing surface flat if necessary.
Install the new thermostat in place with the spring pointing toward the engine; make sure the jiggle valve on the thermostat aligns with the small bump on the thermostat mounting base. This valve should point to the upper mounting stud on the engine thermostat base when installed correctly.
Apply a light coat of gasket sealer to the new thermostat gasket, and install it in place.
Install the thermostat housing and start the mounting nuts by hand, then tighten the nuts but do not over tighten to avoid damage to the threads and thermostat housing. Mount the hose on the thermostat assembly fitting if you had to remove it; plug the thermo switch and install the air intake duct as well.
Connect the black, negative battery cable, and bleed the cooling system. Start the engine and let it reach operating temperature; then, check the reservoir coolant level and add as necessary to bring it up to the Full Hot mark. Using a wrench or ratchet and socket, slightly loosen the valve nut on the thermostat housing assembly and let the air bleed. When coolant begins to leak through the valve, tighten the valve and turn off the engine.