My Wife’s treasured 120 FHC has an oil leak at the left lower rear of the block near where the camshafts oil supply line attaches to the block. I have been trying to stop this leak for 30 years with no success. I suspect the oil supply line and have tried the OE copper crush washers, those washers that have a rubber seal in them, various sealing agents on the washers. I have replaced the oil line and two of the banjo bolts I broke by over-tightening.
I have replaced the cam cover gaskets several times with no success there either.
Any been there, done that with an oil leak in this area??
Considering you’ve tried everything else, I suspect sealing surface damage.
The sealing surfaces on the block and head have to be perpendicular to the tapped threads, and smooth with no divots, chips and scores.
Can you look for damage, get a file or grind stone in there?
