one hot cat

Are you positive the gauge is reading correctly.........the gauge in most trucks isn't exactly accurate. Have you hooked a laptop up to the ECM to see what the ECM says the coolant temperature is versus the gauge? You have more than enough radiator to cool this engine........actually the 6 row is extreme overkill. The thicker a radiator is the harder it becomes to move the air through it. Also the engine fan on these motors doesn't come on until 217*F............so 215 isn't hot yet

 

another excellent post by Mr Haney...
Thank you Kurt

 

i just bought my 1st e-model cat last year,i love the power it has compared to the 425 cat. my only issue is that it heats up faster than the 425,when loaded.if i'm loaded # 45,000lbs it will stay around 200 deg on a hill or when i accelerate from the light.i have the red coolant in the 550.oh yeah my 425 has the thermostat stuck open,so that may be why it runs cooler.

 

Mine runs cooler at 800hp than it ever did at 600hp in fact everything runs cooler except the gear box temp

I put it down to more air pushed through the engine (more boost) in saying that I don't keep my foot to the floor on long pulls either,as long as I keep the EGTs down around 900-1000*F everythings fine.

Like others have said there might be something going on there.

 

There are so many possibilities with overheating you really need to do some pressure and temp measurments to figure out what is wrong and by the sound of it something is definately wrong, no way should it be overheating.
May I suggest start with the basics, is the fan coming on at the right temp? is the fan spinning at the correct speed? if the belts are too loose you will get low fan speed. is the fan shrould in good condition? is the fan the correct depth in the shroud? can the air flow get out of the radiator? the aftercooler or A/C condensor isn't blocked restricting air flow to the radiator? as Mr Haney has said, have the thermostats been checked and are they working ok? what is the water pump outlet pressure (should be a minium of 15psi at 1400rpm)? I would also double check the temp gauge is working correctly with a laptop as suggested.
If you have sound suppression on the sump you can get a useful gain in cooling by pulling it off.

 

Another thing to check for after checking all of that would be look at your Air to air system. Remember you upgraded the Turbo their may be a leak in the plumbing and if their is the engine will WORK HARDER to get the boost it needs. Do not laugh I had a 1998 C120 with a 470 Detroit that would overheat on about every grade out west you can think of even hauling Dispatcher BRAINS. Well the company finally checked for a leak in the Air to Air system and found a leak in it. Replaced the Intercooler and 2 flex joints guess what problem went AWAY. Test trailer was fun Triaxle with a GVW of 97K that engine SCREAMED for relief and only got to 200 uphill.

 

Another thing to check would be the radiator fins. They could be clogged with dirt. I had this issue one time, took an airhose to it and problem solved.