Overheating I have a 2002 Grand Am GT. It has the 3400 motor and overheats within 5 minutes of running. I have changed the water pump, thermostat, radiator,water rail (that goes to the heater core). I have flushed the heater core with water ( both ways) and it flows thru it fine and clean. When it overheats both heater core hoses are hot ( one more than the other). In the antifreeze overflow canister (i guess that is what you call it) it has two smaller lines. one goes to the radiator and the other to a metal line that goes to the upper hose. both of these are steaming hot. I have bypassed the fan and it still overheats with the fan running. It blows no heat. I even hooked a water hose directly to one of the heatcore lines and it pushed water thru the whole system and kept it cool. as soon as i hooked it back up it overheated again. Help I'm running out of idea's. Thanks, Todd

What about the radiator cap?, Try this procedure:

• Dirt and debris can get lodged in the radiator air flow paths. This can block the radiator and cause your engine to overheat and damage the engine.

• The thermostat can be stuck close. If you feel the upper hose very hot and the lower hose cooler than normal, it may be a stuck thermostat.

• Make sure the radiator and the overflow bottle are filled to the proper levels.

• Bleed air from the coolant system:This is best done by running the engine with the radiator cap off until you see when the air bubbles stop coming up.

• Check the radiator fans: The easiest way is to turn on the cars air conditioner and turn up the A/C fans. Both radiator fans should come on when the A/C starts

• Make a pressure test by using a pressure testing tool (available at most auto parts stores). Use the pressure shown on your radiator cap. Most cars are 16 PSI or less, so don't exceed that pressure. Replace the radiator cap if it doesn't hold the pressure.

Did you bleed air out coolant. if you did check engine oil when engine cool .could have a blown head gasket. if it look like milk shake . head gasket leak . reason blow no heat check see heater blower motor working.if yes . heat control unit or heat door not open in dash vacuum line to heat door actutator could be leaking.