one of my old s13 dual cam motors would over heat almost weekly. Same kind of thing, no love for that motor. The thing ran like a dog. It would over heat to the point of stalling out. Let it sit for a while to cool off, then start it back up and beat on it some more. It had a dying water pump and no fans. after a few months of that crap, I gave up trying to kill it, pulled the thing apart, fixed the water pump and other odds and ends stuff, gave the motor to a buddy of mine who still drives on it.