I have a SL2 "00" that overheats in stop & go traffic but if I'm crusing at any speed it will cool down and stay cool even w/ the a/c on.
I also have a SL1 "98" that I canged the thermostat 6 months ago and now it's smoking from radiator but the temperature gage on the dash is only reading to the middle.
If anyone has experienced either of these problems please give me some feed back. THANK YOU!!!

 

on the 00 it soundslike your cooling fan isnt working going down the road with little stop and go is forcing air throught the radiator and in heavy trafic thereis little start by checking the fuse

 

on the 98 i would say if its actually?comming from the radiator time to replace it but check your hoses they may be worn out

 

(00)
with car running, the radiator cooling fan should come on and stay on when the A/C is turned on -- if it doesn't, then check the fuse, the relay and the fan motor itself in that order.

(98) Saturn radiators tend to develop cracks in the plastic side tanks of the radiators right where the radiator mounts to the car....

I would trace the source of the steaming coolant immediately since it sounds as if your car has not truly overheated yet (unless your ECTS is bad and sending a bogus signal to the PCM and the dash sensor.)

How much coolant have you lost?

You do not want to overheat these s car engines---attend to this immediately.