How have you diagnosed the coolers? I agree that it would be the most logical place but have you pressure tested the coolers? Might want to fill the cooler with water after capping off one end and pressurize with 15-20 psi air (make sure you have a gauge on it) and watch for loss of pressure. If it drops over time you have a pinhole leak in it most likely.
I was looking at the water pump inlet area and do not see any way for oil to be drawn in there so it really has to be in the area of a heat exchanger like the oil coolers.
|