If you're fortunate to be able to drive around in a luxurious Cadillac DeVille, you likely want to keep it running in top shape. Rotating tires, changing oil and routine washing are always on the maintenance list, but neglecting the cooling system could lead your DeVille to a long stay at the auto repair shop to have the engine overhauled. A quick change of a couple-dollar thermostat can prevent damage that could cost thousands.
Remove the thermostat housing by removing the two bolts that hold it onto the DeVille's engine, then lift the thermostat housing off the engine to expose the thermostat. In the DeVille thermostat replacement, the radiator hose is still connected to the housing. Drain the hose onto a clean bucket, then push the hose and the housing off to the side so you can access the thermostat.
Pull the thermostat out of the DeVille's intake. It is not bolted into place; remove it by pulling up on it. It may stick if it's been in there for years, but pulling on it should break it loose. Pull the old gasket off the intake and wipe the machined surface off with a clean towel. Make sure every bit of the old gasket is removed; if necessary, scrape bits off with a putty knife or blade. Don't let any of the bits get into the intake.
Place the new thermostat into the intake manifold and place a new thermostat gasket on top of the manifold
Place the thermostat housing on top of the gasket and bolt both pieces back into place.
Replace the excess radiator fluid back into the radiator thorough the filler cap.
