I bought a new gasket for the oil cap, still leaked. I made my own from thicker gasket material = no more leaks. On the breather hose I used a rubber band made from tire inner tube as a constant tension clamp = no more leaks.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked