Change the temperature sending sensor on the engine. This is literally a 25 min. job from start to finish. The sensor's new from Saturn are cheap and notoriously going bad over time. Just did one in my 97 and it was simple and cleared the same problem. The return line from the engne to the fill/overflow tank may be clogged. Take it off and clean it out.
Have it checked out soon and don't let the engine overheat!
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.
Common for a cracked coolant temperature sender. Although there are many other possiblilites. Don't wait, get it figured out ASAP.
Dex-cool
Check the cooling system, and I mean everything. Thermostat, temperature sesnor(s), radiator clogs, radiator cap, badly damaged water pump, belts, you could simply need to add more antifreeze. If it isn't your coolant system, then it's your driving habbits or driving conditions, in which case you may want to slow down, get a car that can handle harsh driving, or upgrade your radiator. Also check that your electric fan is coming on.
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.
The mean temperature on Saturn is 88 K
Use the Gold antifreeze. It lasts longer and does not cause corrosion to the cooling system.