I have same problem...I bought an old 75 240 d without the radiator and oil cooler and i found a radiator to rebuild but the oil cooler i got on ebay--big surprise--is junk.

You can have a hydraulic hose shop make the hoses you might need with any kind of thread imaginable and they will be better then oem because they will use metal reinforced rubber hose. But they might have to be sculpted to fit the necessary contours of engine components.

if i can't find my cooler, i'm going to have to find a universal one and have custom hoses made for it and mounted somehow.

Benjamin