12.7 detroit overheating and everything is new

Is it losing coolant? Bad thermostat, maybe some debris got loose and blocked it somewhere?

 

I believe in the kiss method. Start with thermostats. They are cheap and easy.

 

Also blow out the radiator and CAC. I know you said everything was new but it has been over a year. Look for bent fins on the radiator, CAC, evaporator and anything else in front of the radiator.

You can take the winter front off now too...

 

The mpg drop is probably the latest low nox file
Have you confirmed the temperature numbers with a temp gun?

 

When you have a boost leak the symptoms are overheating in a pull, low power, poor millage. I realize the CAC is new, but so many other places to loose boost from the hose to the air compressor intake gasket etc. That's where I would start. Just because the gauge shows its making full boost pressure doesnt mean thete isnt a leak. Another thing it may be is if the valves were set wrong.

 

I would check for boost leaks as well, but usually your boost pressure will be off and exhaust temps affected .

Overflow tanks cap should be a pressure relief cap, if that cap is bad, it could cause this. coolant will boil at 210 degrees (rough numbers) normally but 230 if in a pressurized system so if the cap isn't letting the system pressurize or your system is venting. ... you'll hest up quick and overheat often.

on my upper rad hose (steel) I have a Allan screw on top that can be used to vent/bleed tge system. I had the same issue as you and it turned out my mechanic didn't tighten it all the way after filling and bleeding my coolant.

 

yes. even my 99 ihc 9300 with a n14 had a pressure cap.... had a spring in it.