replace the valve cover gasket and the 3 spark plug hole gaskets (one gasket for cylinders 1&2, 3&4,5&6). these gaskets are prone to leak, and very easy to replace! the procedure is pretty much the same for the s38b36 as it is for the s38b38, although the b38 motor takes a little longer because you have to remove all 6 coils. this is the easiest option to try.