Last Friday I was sitting in traffic in my '04 6.0L F-250 Crew Cab (5mph at most) when my temp gauge suddenly skyrocketed and coinciding "check gauge" light illuminates! I had noticed the fan kicking on and off quite a bit starting the day prior. The temp gauge went back down relatively quickly (within a couple minutes) and I was able to get the boys to school and to work without any further issues other than the fan engaging frequently while the temp gauge was mid-range. Before I left work that afternoon I checked the rad and the damn thing sucked up 1.5 gal of water! I noticed a good amount of light grey to white smoke when mashing on the throttle a couple times that afternoon on the way home but that has stopped as well. As of right now I have no smoke, truck seems normal and coolant levels remain consistent (loses a VERY slight amount but I tend to think its due to evap). No oil in the coolant that I can see or coolant in oil for that matter and no white spotting on the Degas bottle. I DO notice that it heats up (to mid-range) quicker than normal and every once in awhile when I pull in somewhere and shut down I can hear coolant bubbling in the radiator (keep in mind the gauge never reads past mid-range) so SOMETHING is still amiss. The fan also has quit engaging to the extent that it was and I hardly notice it.

Some more info:
A couple months ago I popped an EGR valve code and CEL. I unplugged it for awhile to see what that did (nothing). Ran it unplugged for about a month and plugged it back in to have the CEL light go out about 10 days later on its own. I drove it for over 3 weeks with NO CEL illuminated until last Fridays happenings. I still have no CEL or indications of malfunction. I've towed my '69 Bronco ONCE a year ago but other than that its a daily driver on the highway and currently has 118,000 miles on it.

I've been reading up on the EGR cooler issues and trying to diagnose my issue if it be a cooler or possibly something as simple as a bad/ stuck thermostat. If it is a cooler I feel completely comfortable with the DIY delete remody thanks to some of ya'lls great writeups. If I go the delete route (being that I've had the above symptoms and possibly a bad cooler already) is there any other cleanup/ repair thats necessary when removing the cooler and re-routing lines? I recently had it serviced (about 2 weeks ago) and they did recommend a coolant flush however levels were fine at that point... I've been thinking of just throwing in a new thermostat and cleaning the EGR valve to see what that gives me but figured I better check with the SMEs (Subject Matter Experts) first to see if that is a waste of $32 and my time with other larger issues pending...

Also, any chance I'd have a trapped air bubble somewhere in the system causing this? Just trying to get a grasp on where to start...

Any advice or expertise is greatly appreciated!
Fungus

 

Its very possible you have EGR cooler or headgasket issues.

 

Your factory temp gauge sound very normal readings from your description, they get up to mid temp range rather quickly and stay there regardless.
As far as your coolant problem, you should get the system pressure tested first as well as the degas /radiator cap.
You can take it anywhere you want really for this but it's always good to find a 6.0 tech so you can get quality feedback on your truck because he can also plug into the obdII port and get a better grasp on what's happening being familiar with this power plant.
This is the first step to a proper diagnosis.
Post back soon.

also, Welcome to FTE, you'll find a plethora of information here at your disposal.