My truck has never, never been above 210 degrees. Even in the middle of summer, it always runs below that. Well yesterday, sitting in line to pick up my son from school, its 105 or so outside, and it took around 30-40 minutes to get thru the line, at a stand still most of the time, I noticed the temps starting to creep up. By the time I made it to the front, I was at around 225-230 engine temp and trans was around 220. Finally got to go and the temps came down to 210 on the highway and the trans came down some to around 215. I wondering if the extreme heat, no airflow, and the headers baking under the hood was the cause, or if something else is failing.

 

Fan clutch or pull the fan shroud to see if there is a lot of debris bugs etc between the ac condenser and radiator.

 

I guarantee your truck has been over 210, if you're just basing the temps on the guage in the dash. Mine doesn't even move from the middle until the actual temp hits around 230.

 

Not enough air going through the radiator or your thermostat is stuck.

I have also seen clogged/valved off heater cores cause the pump to not move enough water past the thermostat to cause it to open.

 

Yes, probably but thats all I have to go by. Its been normal since that day, runs around 200-210 (by the guage) every day all day. I just dont know why on this day it did that. Its got to be the high temps coupled with no air moving and the headers. It has sat an idled before in the extreme heat for a good deal of time and never moved, but I dont remember if its ever been for this long of a time period. I am keeping my eye on it.

 

Its probably just the clutch fan showing its age. Mine starts running hot when its really hot (100-105deg) and sitting still with the a/c running. Mine has gotten as hot has around 230 per factory guage when doing so. You could always upgrade to the electric fans that come in the 2005 and up 6.0l trucks. Im going this weekend to see if I can find some parts to do the change.

 

ok, so yesterday the wife had to go a couple places and I stayed in the truck. Temps were about 90 degrees outside at first place, sat there 30-40 minutes with AC running, engine temps never moved. I stop by lowes so its gets a little cool down while I am inside. The last place we stop, wife goes in and I stay in the truck with the AC on, outside temp is now between 100-105, after about 15 minutes engine temps start to creep up to a little over 210 on the guage, well then we start driving and they go down to around 200 and stay there the whole 45 minute trip home. Yesterday, drove the truck an hour one way, truck idled for about 10 minutes in 100 degree heat, and an hour home and temps never moved. Even had a few full throttle runs in there. It only seems to start to heat up when sitting with no airflow in 100+ heat for 15+ minutes or more. Whats the diagnoses, still think its the clutch fan or the headers baking under there. Later today when the outside temps get up there, I want to let it sit there idling and see if engine temps just continues to rise, or if the fan is actually going to speed up and cool it down. I plan on throwing some parts at it this weekend when I have time, but would rather get parts I need rather than stuff I dont.

 

You really need a better temp gauge to be useful in diagnosing anything. The stock gauge doesnt move for me between 190 and about 220; always points up.

 

Yeah i agree completely^^

 

My truck does this too, I've even converted to e-fans.