So I finally did the pressure test today.
Pumped to 15 psi and it dropped by 4 psi in 10 - 15 minutes.
Could not hear any air leaking from the oil filter mount but the wind did start blowing slightly while we were out there. We did not see anything leaking.
The oil is milky and it's hard to tell if there is any oil in the coolant.
It has never blown any smoke or any loss of power.
After running the upper hose was never hard later on or following morning.
The hose has never been collapsed.

What should I check next to determine if it is the Oil Cooler or something else?
I am disabled and have a friend come over and help me to do this stuff since I can no longer do them.
I am also on a fixed income with nothing to spare so I need to be sure of problem before spending money on a repair.
If this turns out to be HG the truck is gone because there is no way I can swing that repair.
Thanks