How do you replace thermostat on a Chevy Malibu and what are the proper tools to use for this repair?

Open the hood, relieve radiator pressure (make sure coolant is not too hot or you may get burned), Follow large hose from radiator to top of engine where the thermostat housing is, take a channel locks to get the hose clamp off, unbolt thermostat housing, take thermostat out, put new gasket on new thermostat and put in, tighten thermostat housing back on, clamp hose back on, fill up any coolant that you lost, take car for a drive, let it get past the operating temp, watching the thermostat drop back down to operating temp (or temp your thermostat is rated at), shut the vehicle off, open the hood and check for any coolant leaks.

Assuming this is for a 1997 - 2004 model Malibu you will find it easier to complete the job if you remove the throttle body. The throttle body is held on by 3 different 13mm bolts. (There is a fourth nut if you remove the bracket for the throttle cables) The third bolt in the lower right corner of the throttle body is hidden behind the 2 bolt. It is difficult to work with because of the limited room, but a open/closed ended wrench should be fine. There are also two little hose connected to what looks like a heater line, they too are difficult to remove, but a little force will help. With the throttle body unbolted you can move it out of your way (no need to unhook the throttle cables, just unbolt it so you can move it) you should be able to get to the two bolt holding the thermostat housing in place. The instructions above will guide you through the rest. Oh, you may want to also remove the air filter and air filter housing for room. I think the torque specs on the throttle body and thermostat are 18 pounds. Good luck getting the torque wrench to fit, I did the old guess method. As long as there are no leaks afterwards.

Be careful not to destroy your gasket on the throttle body. One less expense. I haven't found it anywhere (book/internet) but I did not have a gasket for the thermostat housing, just a rubber one around the thermostat its self, but the new one came with a replacement.

You may want to your your ODBII scanner to delete the pending "temperature below threshold" check engine light.

Tools Needed for the Job:

- Deep metric socket set

- Standard metric socket set

- Various size flat head and Philips head screw drivers

- Gloves

- Open and closed metric wrenches (sizes 8mm - 15mm)

- New thermostat (195 degree)

- 4 hours

- 12 pack of your favorite beer.