Coolant in oil, not the usual problems???

My brothers truck has started getting hot a few weeks ago. We checked the thermostat to see if it was sticking, upon removal we noticed oil in the coolant, we pulled the dipstick out and it looked like mud on the dipstick.



Coolant was in the oil too.



A few months ago I replaced the head gasket with a cummins gasket and did all new seals, but I figure it was possible with it getting hot that it may have blown the gasket again... And yes I checked the head for straightness and followed the torque sequence, I've done quite a few of these.



Today we removed the head figure it might be blown.

But the gasket looked perfect! No blown out rings and any noticeable imperfections.



So we also pulled the oil cooled, I capped off one the holes in the cooler and blew air, only 15psi, through the other hole. I did the in a tub of water and didn't see any air bubbles.



A friend of mine recommended pulling the tappet cover to inspect the freeze plugs, I did that as well and the seem to be in perfect shape.





I'm curious to see if I'm missing anything?



Do you guys have any ideas, or have you heard of a similar scenario ?