M112 2.8L Oil Pressure Test Port leak, need specs.

[Nektopoli]

1998 C280 with 152K, old oil pressure test port started leaking so I pick up the updated cover and gasket and a new bolt with crush washer got everything installed and it still leaked, flipped the gasket around and still leaking. I tightened the E-10 bolt to 13nm and it poured out so I tightened them by feel some more and it reduced the leak to a constant drip. Some have suggested that I run a bead of Blue RTV along the edge of the cover and that the cover and gasket will never seal correctly without it.

NP