I've been dealing with an
oil leak in the same area. In the past, all fittings were tight, and the bolts weren't leaking as those bolt holes are blind in my alloy block. The leak was coming from somewhere around the perimeter of the adapter.
I found another adapter on the internet that has more surface contact area against the block. I also applied a very slight amount of Permatex Aviation Form-A-Gasket on both sides of the gasket. I haven't tested the new adapter and gasket yet, I'm about 3-4 days from first start-up for this season.
