I have a 2001 grand Am that over heats on a constant basis. I have changed the radiator, hoses, thermostat, and water pump. We have cleaned out the lines and removed as much sludge as possible. Removed the guts from the thermostat to no avail. I will run ok for awhile then overtemp. Oh by the way we changed the things listed above twice just in case we got a bad one. The water pump side of the radiator will warm up and the other side will overtemp. I am lost at this point. The heads had been checked and they are not warped or cracked.