Coolant almost overheating solved

I'm slowly chipping away at the problems with my '89 2.5 Shadow. Many of the problems are past owner poor maintainence and just plain messing things up. It has been heating up to the point of almost overheating, then the fan would cut on and the temp gauge would fall rapidly to normal. When you cut the car off in the hot mode, it would churn half the radiator contents into the overflow tank. The thermostat housing looked to have newer gasket sealer showing, indicating a thermostat replacement. I thought I would start there anyway and work through the coolant system. Took the t'stat housing off and found a new t'stat installed BACKWARDS. The temp sensitive side was bathing in the cool radiator coolant so, as the head started to cook, heat had to transfer through the metal of the t'stat to the works on the other side then open. I wish stupid people wouldn't work on their own cars :)

That's pretty funny actually, just because it was put on wrong. You'd think that whoever put it on would have noticed something WORSE going on after installation of this thermostat. At least you got the problem figured out, though.

Yeah, I'm being a little harsh on who ever did it because the t'stat is stamped with "to radiator" on the motor side and a hard to see arrow pointing the other way. As you said, happy ending. Now on to solving other little gremlins.