Getting warm 2011 Cummins ISX on International prostar

Is there pressure in the overflow bottle?

 

this is what I would do in this situation. Start her up in the morning, get her up to temp, take her out on the road and give her hell while going for a cup of coffee. Bring it up to higher gears where you can build some boost. Drive it like you stole it. Then come back home and observe how it acts while idling and cooling down. Never know, maybe work out whatever bugs in the system

 

Good luck; might just be air-bound somewhere in there. If you got a steep bank you can nose up on,
Try it first in forward and then reverse; might just "Burp" the air out of it's innards somewhere.
Hit the brakes to jiggle the coolant front to back to get it to move around in there.
Sounds downright weird, but I did that with my Backhoe that was overheating - and it works now!
The Temps you describe and fan kicking in seem normal and ok; but you know your baby and her ways.

 

Just re-read this thread and two things pop out at me.
I replaced starters one time - and got 3 in a row that were bad. Yes, I was extremely pissed.
Nowadays, new doesn't necessarily equate with good. China makes cheap, not good.
Also, The suggestion on testing the thermostat will positively eliminate that as a cause.
It will cost you an hour and a gasket, but what if you find it opens only partially, or opens at 195?
Thermostat should be stamped with temp. - check it. Is it correct? Get a Stant or Gates, not China.

 

I agree with this statement. If all else fails, I'm pointing fingers at thermostat again. Some motors require 2 of them. After the shake down cruise I would look into them again. Look at it this way, if yours are stuck open, the truck wont even get up to 180 degrees at idle. it happened to me a few months ago. the #### thing wouldn't get up to operating temp with the fall coming. It would get up to temp when running her loaded though. But at idle it wasn't doing crap. I was worried with the winter months coming I was gonna have a big issue. Seems like this guys problem is it isn't opening all the way and getting just enough cooling from when the fan kicks on. IMO that fan should be rarely coming on at all with these cool outside temps. I never hear my fan come on now because the outside temps are cool enough to keep the radiotro and fluids cool while driving and idling