1993 saturn sl2

My 95' sl2 does the same thing. When you're on the highway it is getting alot of airflow and the airflow and the ammount of rpm's keeps it cool. While idling, it is sucking warm air from the engine compartment and outside but there is no airflow... I'm thinking about replacing my thermostat from the stock 190 degree F to like a 160F just so it doesn't get warm as fast. The thermostat costs about $10 and is very easy to replace. It can be done in under 30 min.

You probably have already checked, but is the coolant level good? Check when cold.

Probably a problem with the thermostat. If I remember right, this was a $30 part and about 5 minutes to replace.

From what I hear, this is a relatively common problem. My SL1 does this, and heats up even higher in the drivethru than at the autocross, but my mechanic found out that the fan's switch is on the ground rather than the hot wire, so it's rather difficult to override without risking the onboard electronics. Generally, the easiest way to counter the problem is to either become a hypermiler and kill the motor whenever you stop for over a few seconds, or turn the heater up all the way when you see the temp rise(what I do). I have a feeling you'll probably just replace the thermostat, but I figured I'd throw the no-cost fixes on the table to consider.

I have a 1994 SL1 1.9L 4cyl SOHC that does the same thing. It needs either a thermostat or a coolant temp sensor, or both. I also getting a burning plastic smell when I sit for too long.