The thermostat in a Pontiac Grand Am--indeed, in any car--is a little heat-sensitive valve that is responsible for letting the correct amount of coolant flow into the engine to maintain an optimal operating temperature. Changing the thermostat on a 1995 Pontiac Grand Am is a little different than it would be for most cars because the thermostat is not located in a conventional location. Fortunately, while different, the process is not especially difficult, and can be completed with only an hour or so of work.
Disconnect the negative battery cable from the Grand Am's battery. While this is not strictly necessary, it is good practice when doing any kind of auto work to make sure there is no active current running through the vehicle.
Raise the Grand Am off the ground with a hydraulic jack and then lower it onto jack stands.
Position the bucket under one of the Grand Am's radiator hoses. You will be draining the coolant out of the radiator and into this bucket so as to prevent spills while working on the thermostat.
Loosen the hose clamp on one of the lower hoses with your flat-bladed screwdriver, then pull the hose away from the Grand Am's radiator to start the coolant draining into the bucket. Once it has drained, seal the bucket and place it off to the side.
Locate the Grand Am's thermostat housing. This can be found between the engine and the firewall on the passenger side of the vehicle. If you are having difficulty locating it, follow the largest hose on the upper portion of the radiator until you find the piece it connects to. This is the thermostat housing.
Loosen the two retaining bolts with your ratchet and socket set, then pull the thermostat housing up and away from the Grand Am's engine to expose the thermostat.
Grab the handle of the thermostat and pull straight up to remove it from its setting. Once the thermostat has been removed from the engine, you may discard it.
Use your razor blade--or a scraper tool, if you have one--to clean the remnants of the old thermostat O-ring or gasket from the bottom of the thermostat housing and from the thermostat setting. It is important to get these points as clean as possible to ensure a good seal and to prevent coolant leaks.
Apply a layer of gasket sealer to the bottom of the thermostat housing and press the thermostat gasket against it, making sure it sticks firmly.
Install the new thermostat into the thermostat setting, then replace the thermostat housing and secure it down with the two retaining bolts.
Replace any hoses you may have loosened or disconnected during this procedure, then lower the car back to the ground, take off the radiator cap, and start the Grand Am. Let the vehicle run until the large upper radiator hose is hot to the touch, then turn the car off and pour the coolant back into the radiator.
