After pressure testing the cooler and hoses it appears I have a oil leak at the seal between the 16mm to AN-8 steel adapter and the 1st gen early model cooler threaded bungs. When the system was first put together Stat-O-Seals were used but they began to leak after about 5 weekends even after subsequent tightening. It appears the flange on the fitting has an OD that is not much bigger than the rubber insert of the Stat-O-Seal.

Yesterday, after putting everything back together and using aluminum crush washers it leaks even worse. OEM crush washers are NLA. I have not tried Dowty seals and am concerned because the AN sized units have an ID that is a bit larger than 16mm. There are metric sized pieces but Google showed only a place in the UK and Australia.

Any ideas?