[mueller944s2]

how far is the needle moving up? It should be pretty stable. At idle it'll move up slightly, and when I say slightly I mean not much at all! I was always told that 944 temp gauges move up and down and it's normal, until I put in a different engine and the gauge is now steady all the time. Personally, I open the bleeder valve and blow through the expansion tank until there isn't any more air, THEN I idle it for a few minutes and put it up on ramps and rev it while bleeding. I do this for the next couple days while all the bubbles work their way out of the system. If the level in the tank is still dropping then air is in the system. Also, the fans have two speeds. Maybe the sensors are bad if you aren't getting high and low speeds.

I chased a temperature problem for 4-5 years. Sometimes with a leak and sometimes without. When I put in my 3rd engine the problem vanished, and I have NO idea what it was. I would tighten one thing and a leak would pop up somewhere else. All the hoses were new, radiator, heater core was new. Eventually I got the chance to start over when engine #2 blew. I guess everything got retightened and checked? Who knows.