I was wondering if anyone knows what this is. 2006 Expedition 4wd with 5.4l.

4-6 times in the past 2 years, after driving 10-15 min, the audible temp alarm will trip, making me look at the gauge, which is pegged. After the 2nd time I realized it was a false alarm as I would turn the key off and on and it would reset to a normal temp. I also observed no excess heat coming from the heater (which I turned on) or the engine itself when I opened the hood.

The last time this happened it wouldn't reset for long. 10 seconds would go by and it would alarm again. But that was last week and it's been fine since.

A local shop reported no related codes, and claimed they could only pull a code when it was happening. Not sure when that's going to happen next.

Anyone have any ideas? I saw one string where the same symtoms turned out to be a cracked block. But I'm just not seeing symptoms of that. No coolant smells or leaks, no excessive engine heating, etc.

Thanks!
Kevin

 

Have you replaced the coolant temperature sensor yet?