Make sure the radiator fan is working. Your thermostat is broken.
Any type of antifreeze will work in a 99 Saturn SL1. Many people recommend using Prestone Antifreeze for cars that are older than ten years.
Dexcool
No vehicle actually burns antifreeze. If the antifreeze level in your Saturn seems to be going down, it's because of a leak.Possible antifreeze leak locations are:Coolant hoses.Radiator cap.Water pump.Heater core.Head gasket.Cracked head or block.Find out where the leak is occurring and repair it.
Dex-cool
The 1997 Saturn used dexcool antifreeze. The chemical compounds are different and should never be mixed, as the engine will no longer cool properly.
To change the antifreeze on a 2003 Saturn Ion-3, locate the drain plug on the bottom of the radiator. Drain the liquid into a pan before refilling it.
Anti-freeze that is compatible with aluminium engines.
Use the Gold antifreeze. It lasts longer and does not cause corrosion to the cooling system.
Match the color of your antifreeze to the new one you buy unless it states its good for all types.
Autozone/ advanced auto usually has antifreeze that goes with either kind. I suggest that.
You will need to replace the heater core.
Boil over? As in antifreeze? that's probly a blown headgasket