Originally Posted by adamdf

FYI: I was using 89 octane fuel. When we started the climb, the outside temp was roughly 100 degrees and I think the problem is that heat gets trapped between the rock walls on each side of the road as you are gaining in elevation making it a very difficult climb for all vehicles. There were probably four maybe five vehicles along the way that were pulled over on the side that had overheated. When we got to the campground, we were going thru all the potential scenerios in our mind as to why this might be happening because my brother-in-law said the temp gauge needle on his 5.4L never moved. We think my truck must definitely be malfunctioning. We checked the fluid level on the radiator and it was OK, and the radiator was not overly dirty (normal bugs and a little debris). I called the local ford dealership (this morning), here in flagstaff, and they want to keep my truck for the day to run it thru a diagnostics test but I can't leave it for the day because we are on vacation and they don't have a loaner vehicle to give me. The transmission temp gauge never moved at all and up until I started these two climbs, my temp gauge needle never moved at all. We stayed at the Davis Mountains state park and I had no problem traveling into the park the day before. It was only when I was going up the two 5 to 6 percent grade climbs from Phoenix to Flagstaff that I had a problem. My dad was thinking the thermostat could be malfunctioning (not sure what kind of technology they have on these new trucks). I was very stressed trying to make it to the top without damaging the engine (although the computer reduces power automatically to prevent that from happening, I was stilled very stressed out about it). Anyway, I may stop by the dealership here in the afternoon to talk directly to a service tech and see if he can hook it up and tell me something without having to leave it for the day...stay tuned.

Originally Posted by rjlittle53

Thanks I will check it out. My truck is at Camelback Ford and has been sense last Thursday. They were going to check the thermostat operation and then go from there. The service writer said that the Ford engineers admitted they have had problems with the Ecoboost overheating while towing!