Car running hot after it warms up --

Saturn mystery

99 Saturn SL1 with 146k miles. A few weeks ago during my daily commute, the service light came on. A few moments later the light came on again for a few moments and went off again. The temp gauge started climbing – i could see it rising. I pulled off, checked all my fluid levels and didn’t notice anything out of the ordinary. I have replaced the thermostat and the EGR in this car before. (3-4 yrs ago) On driving home from work one day, the service light came on and as I sat in stop-and-go traffic the temperature started to creep up and up until I turned the heater on full blast. I have noticed that the service light only comes on when the RPM are at 2700 or higher for longer than 1 minute. After the engine cycles back down to a lower RPM the service light turns off again.

The heat issue is still presenting itself. Could it be a faulty thermostat?

Yes,it could be the thermostat, or it could be inoperative radiator fans.

Are the fans working?

I wonder if it any of those Saturn’s run hot before they warm up? ?

BTW I agree with mcparadise.

It might be a lack of coolant or pressure in the system inoperative fans(thanks mc), ie not the level of fluid in the reserve tank. It might be a sticking thermostat, It might be air in the system, it might be a bad sensor. If all is correct it will work correctly.

Check the simple things first.

But I have to mention the elephant in the room: Aren’t these years of Saturns known for head gasket problems?