The oil pressure gauge should work since it reads directly off of oil pressure at the oil filter housing. Check the P/N of the coolant temp sender for the 2 model years. If they are the same, it should work fine. If P/N's are different, it may till work, i.e. different physical dimensions but same resistance/temp curve.

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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