I just changed the thermostat and the heater hose connector on a 2001 Grand Am with the 2.4 L engine. I found absolutely no correct information on this subject anywhere on the internet, so count yourself fortunate that you have found this.
First, Raise the front end of the vehicle on the passenger side. Once it is safely supported, crawl underneath and follow the lower radiator hose back till it connects to a steel tube. This tube is also the thermostat housing. It turns and goes up to a location between the trans-axle and the exhaust manifold. Just past the connection point of the hose, there is a support bracket that is bolted to the engine. Remove the bolt from the bracket. If I remember correctly, it will require a 13 mm wrench. Next lower the vehicle back down. Leaning over the fender on the passenger side, look behind the engine and you will see a heat shield that covers the exhaust manifold. It is held on by three bolts that are threaded into the exhaust manifold. I recommend soaking them with a penetrate such as Kroil or Liquid Wrench because they may be seized due to the heat and corrosion. You will need a 1/4 " drive ratchet and a short extension with a 10 mm socket to remove the three bolts. Once the heat shield is removed, look down between the exhaust manifold openings, to the left side, and you will see the location where the thermostat housing is attached by two bolts. Using the 1/4" drive ratchet, an 8 mm socket, and multiple 1/4" extensions, you can reach both bolts. Remove the two bolts and the thermostat housing will drop down allowing access to the thermostat. Reach down around the rear of the exhaust manifold and feel for the thermostat. It will likely be stuck in the upper housing. Remove it along with the rubber seal. Take a new rubber seal and coat it with a silicone grease and install it around the outer edge of the new thermostat. With the pointed end of the thermostat pointing down, place the thermostat and seal into the lower thermostat housing. ( You need to be sure that the thermostat cylindrical side is toward the engine when installed.) Depending on your height, it may be easier to do this from beneath the vehicle. Raise and safely support the vehicle and crawl back underneath ad raise the thermostat housing tube into position. While holding it there, re-install the bracket bolt. Next, lower the vehicle back down and then re-install the two thermostat housing bolts. If you are replacing the heater hose quick connector, which I recommend once the vehicle has overheated because it is made of plastic and may have been weakened, follow the 3/4" steel tube from the top of the thermostat housing toward the drivers side and you will come to the connector. Pinch in the two side clips on the outside of the connector and slide it off of the end of the tube. Next pull the hose up and remove the clamp and connector. Using a small amount of silicone grease, coat the inside seal of the connector and reinstall it in the hose. Tighten the hose clamp, move the hose back down into position, and then slide the connector onto the tube until it seats. Next, set the heat sheila back in place. Take the three bolts from the heat shield and apply a small amount of anti-seize to the threads. Reinstall the three bolts. Now you are ready to add your anti-freeze and water mixture to the reservoir. Once full, replace the reservoir cap and start the engine. Let it come up to operating temperature and check for leaks.
Thursday, August 22nd, 2013 AT 6:12 AM