I carefully compared the new gasket to the old one, and all the holes and passages were the same. Only difference I could find was a better rubber seal around some of the water passages. No RTV sealer (or any other sealer) used anywhere on the head gasket.

The oil drain galleries are slanted in the head, do they continue in that direction in the block? or are they vertical in the block? I heard of a similar case happening with an older VW diesel, but never found out what the cause was.