I just got back from pulling the new Fuzion over 500 miles. I have started to have a problem with the truck temp gauge and throwing a code. I have looked over the site, and found a few posts somewhat like mine, but either no posts with the fix or the truck is a first or second gen.
While accelerating to highway speeds after slowing/ stopping for toll or traffic, I will hear the "Ding" and the Check gauge light comes on, at that time all gauges are normal, but the temp slowly climbs and reaches the space between the black and red line. I slow down and start to pull over and then the temp slowly drops back down. I hear this fan like noise while the temp is changing, but goes away when back to normal. I have also noticed the time between ding and normal is getting longer, I think, each time. The truck seams to run fine after back to normal.
This has happned to me multiple times this weekend on both flat and climbing a grade. The truck throws the code P 0217, Engine loosing power due to overheating, although I can not say if for a fact the power loss is noticable.

Any ideas? I am not afraid of my Local Dealer, they have been great with my tranny problem and fuel pump replacement (all the normal problems). I just want an Idea before I go in and point them in a direction. They respond positively and actually appreciate something more than "fix it, it don't run wright".

 

How many miles do you have on your truck? Sounds like you might have a bad thermostat, or water pump, or dirty used up antifreeze.

 

Little over 96000. I thought that also, but why does it do it after slowing down first, then speeding up?

 

I am going to say you have a transmission problem. The fan noise you hear is the engine fan coming on to cool things off. It cools off quickly because that fan can move some serious air. I had this problem with a high mileage gasser. Towing a camper it would get hot. I changed the thermostat twice, flushed the coolant system, got an very expensive over sized rad, nothing fixed it. When I finally realized it was the transmission slipping I got rid of it.

I don't know if the dealers scan tool can measure transmission slip, I bet it will. But assuming your cooling system is good and the rad is not clogged with junk inside or out, i would hook up the camper and take the tech and his scan tool for a ride. Let him monitor trans slip while under load.

Let us know what you find.

 

I know it's obvious, but you DO have coolant in the system and your expansion bottle is up to full, correct ?

 

I have coolent in and at the last oil change the shop tested the coolent and said it was good. Hard to see where the line is though on the overfill.
More info on what is going on. Yesterday I went for a drive and 2 miles into the drive I got on the highway and felt rich and floored it. Temp outside was 75. When I got to 70 mph I heard the ding and the truck did the same thing, engine temp went up slowly after the ding and then went back down. I did not have a load. Now after I had the truck warm, I stopped and turned around and tried it again and this time it did not do the temp change thing. So, I am thinking it may be the thermostat waring out (06 Diesel thanks for the tip, took a bit to sink in). I also noticed that the running temp is above center a bit, where as in the summer while pulling or not, the temp was at 200 spot on. Is changing a thermostat something a hack with few tools can do on the 5.9? I have changed a thermostat on my Ford Ranger before. Is it on top where the hose goes into the block?
NickBeet, this summer I had the trany worked on, they replaced the Governer valves and adjusted the bands. I was starting in second, problem began after the first trip with this trailer. The dealer fixed it and all was good. So I hope it is not the trany. I feel ok to throw a few parts at the truck if I can do them in my driveway.

 

Put in the Thermostat and things seem to be doing well. Temp is now below 200, but outside air was 55. Pretty easy, 3 bolts and swap. I'll take the wait and see approach if this fixed the problem.

 

I hope you got it fixed. Hook up that camper and find out.

 

My truck is doing this exact thing. The check gauge light comes on and the temp gauge is pegged. Then the gauge will start to drop and go's a wild a few times jumping fully to 240+ then drop back to say around 210. I pulled over and checked the engine but it doesnt seem hot. The tranny does shift kind of strang at low speeds and I can hear the big fan running hard. The strange thing is theres no smells of heat or any kind of heat coming off the truck or tranny.
Kind of a strange deal, it just started happening and the gauge will drop to normal if you shut the truck off for a few minutes, then when you drive it the gauges and tranny start actting up again.. Temp outside is very cool also, mid 50's or so.
Anybody else have this with a 06' model? It's off to the dealer in the morning I guess.