Wow! I've never solved one of those nail puzzles but didn't have much trouble at all with the oil cooler lines. (Not bragging, just puzzled by all the problems folks are having.) All I did is remove the motor mount and jack the engine about 1" for a little extra clearance to reinstall the clamp.

Here are a couple of things I found that helped with removing the line from the filter housing. Take an inexpensive box end 1 1/16" and use a dremel tool to cut and make it a flare nut style wrench. Double wrench with a 42mm line wrench(thin) on the nipple fitting. Putting the wrenches in close enough proximity to use hand grip pressure to break them loose saves on rapped knuckles.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )