I recently picked up another 93gs300 and it overheating. i havent checked the cap or thermal stats, but its not leaking oil, no milky oil cap, not loosing coolant, no smoking, and the clutch fan is functional. When the car over heats or after i park it, thoses a hissing noise coming from around the radiator cap.

i took it to go get smogged today and it failed. it ran rich, so the cat converter could be clogged or o2 senor is bad. any ideas if this could be the overheating problem or where should i start.

also it is not throwing any Check Engine light.

update. i changed the thermalstats, and flushed the radiator. and its still overheating..

 

You need to replace the thermostat, and gasket. I bet thats where your problem is. You also need to flush the coolant system with Toyota Red coolant ONLY. No GREEN, No Oragne, NO other brand of red. ONLY Toyota Red. These engines have an iorn block and an aluminum head, they let off minerals, and Toyota Red blocks them from forming algea, ect. in the engine coolant system. If it isn't the thermostat (which I am 98% sure it) is, then post back here. There really isn't much else it could be. Is the Fan shroud still there?

 

fan shroud is still there. turns on the last owner pop the fuse on the RDI FAN. and the fan wasnt turning on. but now the temp stays in the middle but will flicker up and down as i stop in traffic

 

anybody got an OEM radiator cap??