Ummins ISX15 Random Overheating

[iAMTrucking]

I have a 2011 PETERBILT 387 with a Cummins ISX that is randomly overheating and or running warm.

I took it to the shop, they tested and let idle for 8 hours and it did not run warm or overheat. They gave truck back to me. I let truck idle for 1 and half hour before leaving...Truck started to heat up past 220 and climbing. I turned the keys back over to shop to recheck.

They replaced fan clutch, pressure tested system and changed thermostat. I picked it up and prepped to go back on the road.

I idled truck that evening while sleeping...just to see. I woke up after 6 hours of idling because AC stop blowing cold...Truck was starting to overheat. It overheated until it did an emergency shutdown due to being to hot. Shutdown at 235. I took pics to prove to shop.

They recommended dealer...so truck now goes to Peterbilt. After 24hours and several hours of idling, test for cracked sleeve, head and or gaskets, Peterbilt states, "unable to duplicate complaint".

At this point, no one has a resolve. Peterbilt has recommended allowing Cummins to put it on the Dyno for stress test, etc. in an attempt to duplicate?

Any suggestions...I am baffled.