If the temperature gauge in your 1994 Toyota Camry hasn't been staying around the 200-degree mark, it's possible that the sludge that is found in older coolant systems has taken a toll on your Camry's thermostat. The thermostat in a Camry doesn't work the same way as a thermostat in a home. In a car, the thermostat is "in line" with the cooling system, and the thermostat is subjected to the liquid that travels through the engine. When it fails, your engine will not heat properly, and it must be changed.
Remove the radiator cap to release the pressure that is inside of the coolant system. This will prevent coolant from spraying out while you remove the thermostat. The engine should be cool when competing this step to ensure you are not burned when removing the cap.
Trace the top radiator hose to the point where it connects to the engine. This is the location of the thermostat cover. the thermostat is located under the cover. Remove the radiator hose from the cover by loosening the clamp that holds the hose to the cover. Once loosened, pull the hose off of the cover.
Remove the cover by removing the bolts that hold the cover onto the Camry's intake manifold. There are two bolts; one on each side of the cover. These bolts will be reused, so they should not be discarded.
Pull the old Camry thermostat out of the intake manifold. Remove the old gasket from the base of the intake manifold. It may have stuck to the bottom of the thermostat cover. If it has, it should be removed. Discard the old thermostat and gasket.
Place a moderate amount of PVC gasket maker around the hole the thermostat was sitting in. Due to the age of the Camry, using PVC gasket maker instead of a gasket will help to prevent leaks if there has been any warping of the intake manifold. Allow the PVC to "skin over" or firm up for 10 to 15 minutes before proceeding.
Place the new thermostat into the hole the old one was removed from and place the thermostat cover over the thermostat, lining up the mounting holes. Tighten the bolts back down. The PVC gasket maker will squeeze out. This is normal.
Place the radiator hose back onto the cover and tighten the clamp down. Place the radiator cap back on and start the engine. Once the engine has warmed up check the radiator hose and thermostat cover for any leaks. If there are any leaks, tighten the clamp and the cover down tighter.
