I'm almost sure you're referring to the fan motor. It's not too complicated, but I recommend that you pick up a Haynes or Chilton manual for your car. It will have complete directions and photos.
If memory serves, it's on the front, straight down from the radiator. I think you can see it from the engine bay.
The radiator cap is on top of the radiator. It is located near the front of the engine compartment towards the right side of the car.
It's located on the engine side of the radiator. Lower passenger side. You have to get under the car to access it though. You can't see it from the top.
WHERE is the timing mark on Pontiac sunfire 2.2l
Open the hood on your Sunfire. Remove the radiator cap from the radiator overflow bottle. Turn the engine on in the Sunfire, and let the engine run for no less than 15 minutes. Set the dials on the heater control panel to full fan speed, full heat, and front defrost positions. This will speed up the processes of heating the engine to full temperature. Removing the radiator cap and performing these procedures will allow the pressure in the engine to build up. As the pressure gradually increases, the weight of the coolant will force air bubbles out through the radiator overflow bottle hole. This process is called bleeding the cooling system. Turn the engine off when you notice that there are no more bubbles coming from the radiator overflow. Top off the radiator overflow bottle with fresh coolant. Use 50/50 diluted, universal coolant to fill the overflow. Replace the radiator cap when the reservoir is at the "Full" mark. http://www.ehow.com/how_7734216_bleed-system-Pontiac-sunfire-22l.HTML
heater core has a leak replace heater core
The radiator may have debris that needs to be flushed out.
Check on the engine side of the radiator, one of the two lower corners. It can be hard to see and get at. Mine was a small plastic flat blade, sort of like a key.
4 cylinder engine 2.2 or 2.4
IT IS LOCATED ON DRIVER SIDE OF ENGINE BEHIND THE THERMOSTATE HOUSEING IT HAS TWO WIRES YELLOW AND BROWN HOPE THIS HELPS
thermostat? engine size?
0.040 in - verified, page 6-64: