over heating

Charlenerene,

Things to look for:

Make sure that the system is bled and free of air.

Check for leaks if the system is loosing coolant.

Check for proper operation of the new thermostat.

Check for proper flow through the radiator.

Check for proper operation of the cooling fans.

Also, when you posted, you initially stated "i have a 2002 pontiac grand am, 4.3 v6". Most people (myself included) are going to assume that you have a 3.4. Let us know if this car has actually been modified.

Post back with your findings or if you need help testing these items. We'll be glad to help. Thanks.

charlenerene,

In addition to what's already been posted here's a quick and easy test for a blown head gasket. There are more tests for blown head gaskets, and if necessary we'll give them to you, but for now do this one and post the results.

Remove all the spark plugs. Get a cooling system pressure tester and pressurize the cooling system to about 15 PSI. Leave the system pressurized for several hours. Now lay down some clean paper towel along the cylinder heads where the spark plugs were. Crank the engine over for a few seconds. Since the spark plugs are not in place any antifreeze that leaked into the cylinder will be blown out onto the clean paper towel. Examine the paper towel for the signs of antifreeze and you will be able to tell which is the guilty cylinder.

Yes I meant 3.4..oops! Thanks for the advise. Tried getting air out of system. When it first starts heater works then heater stops working and temp rises quickly. I will attempt all other options you advised.

How do I check the thermostat and radiator though?

Charlenerene,

Was it overheating BEFORE you replaced the water pump and thermostat?

Are you sure you installed the thermostat with the SPRING into the engine and not the other way around?

Did you use an OE water pump or an aftermarket pump? If aftermarket that could be your problem. Pump impeller designs differ on aftermarket pumps. GM vehicles don't not respond well to impeller designs that are NOT "OE". On ANY GM vehicle you MUST use an "OE" water pump or fuel pump.

At anytime (before or after) have you noticed engine coolant boiling into the coolant over flow reservoir?

Are the upper and lower radiator hoses getting equally hot?

Forget about everything you've ever read or heard about bleeding air from a vehicles cooling system. There's only one way to do it. That way is buy a "Prestone Flush and Fill Kit" from an auto parts store, and install and use the kit by following the enclosed instructions.

You should also do a compression test (and/or) a cylinder leak down test and post the results.

Get back to us with answers and results to all the above.