When I put a radiator in my '97 K2500 7.4L, I had problems getting the lower oil cooler hose off the radiator.
Those hoses may or may not leak on my truck. It doesn't get driven enough to notice; and when I bought it the power steering leaked terribly. That side of the engine compartment is a slimy mess.
Anyway, I had to cut the steel tube in that hose assembly, remove the radiator with the stub-pipe still attached, and then free the hose/threaded fitting once the radiator was out of the vehicle. I put it back together with a 1/2" compression union rather than buy a new hose.
I'm told the Dorman aftermarket replacements use aluminum tubing where the original equipment and ACDelco replacements are steel tubing. In both cases, they've crimped the tubing to sections of rubber hose. That's the same way they build PS hoses which take more than ten times the pressure as the oil cooler hoses. I have no idea why the oil cooler hoses have such a bad reputation. One wonders if it's the hose assemblies leaking, or the seals/fittings at the ends.
Point is, maybe you want to use a car-wash pressure wand to spray-clean the hoses, adapters, etc. and drive the truck to see where the leak is actually coming from.