Oil??

If I read you right and your using stock type steel shim gaskets you need to completely seal both sides of the gaskets like the factory did. I use Fel-Pro blue sealer in a can (sorry I don't remember the exact name but it is a shellac type sealer) and never have any problems when I use steel shim gaskets. But personally I don't like the steel shim types as well as their not forgiving for minor surface warping and require sealer. Use Fel-pro replacement gaskets and you don't need sealer except on the end seals and possibly on the bolts to keep oil from wicking up through them.