2001 GT 5 speed 85,500 miles. After burping the radiator hoses, changing the thermostat and radiator cap, filling coolant numerous times and searching all over the forum for answers. My problem of losing coolant and fluctuating temperature remains. I filled it yesterday burped it again and today, after filling the resevoir last night it was nearly empty again this morning. It's time to pull out the big guns and have it tested by a professional. He is a good friend of mine on a local forum and a career mechanic. He is almost sure I have a bad head or head gasket. I have look for provisional signs of this i.e. bubbles on the dip stick, chocolate milk colored oil, bluish smoke out of the exhaust and there aren't any signs of a bad head gasket based off those things, but he's going to be doing compression testing and probably leak down too. He considers a head gasket an easy job. I did one on an old thunderbird turbo coupe I had once and it was far from easy in my honest, but non professional opinion. I'm crossing my fingers and hoping for the best or at the very least a reasonable price. Since I know there have been several threads on here about this issue, maybe this will turn up some new answers for you guys having problems with this same thing. I'll keep you posted.