Good point on the question of "why did they put the oil cooler in the vee"? Ford did the same thing with their 6.0 International diesel. They did not have a leak issue, they had a coolant side clog issue which would snowball and cause EGR cooler failure which then caused head gasket failure. No clue why they both don't place these somewhere external. Of course I guess you could say that about half the parts on the engine which would then require an engine compartment of a mid 70's Cadillac.