Hey Dave. I've been searching for some answers and I think you might be my holy grail. I just bought an 87 f250 with a 6.9. The engine is not overheating, but the temp gauge is pinged at its hottest point. I know its not overheating because it does this right as the engine is started and doesnt change at all. Also, I just replaced the water pump and stat and hoses and flushed the radiator..

I replaced the sensor on the left of your infamous picture of the two sending units, and it's still doing the same thing. Do you think I have a short in the wire or is there some magical crazy thing that I am missing? This truck drives like a dream and although i am 100% positive that it isnt overheating, I am still apprehensive about going anywhere until I can get this sorted out.

I've been coming here for a while checking out little tidbits of info over the years, and the knowledge here is completely insane. I love it!