Mark,
It sounds EXACTLY like my car 2 months ago when I lost the water pump. I'd be willing to bet a lot on it. I would start it up cold and it would take about 10 minutes for the temp to skyrocket. Fan wouldn't slow it down. It would build up enough pressure to blow coolant out the overflow. If you shut it down quick enough you probably saved the heads. My impellar was broken in two places. By the way, my mileage was 39,800 when it went. Good luck. Roy
