I changed my spark plugs and noticed oil in the bottom of drivers side middle cyl. Replaced BOTH Valve Covers (rock auto VC) and the driver side was leaking and still had oil in the tubes. Me and my friend (who is a mechanic) took the VC back off and reseated it with a new gasket (and a small bead of RTV on the whole thing + on tube seals) and there is STILL OIL IN MY TUBES. No longer leaking on exterior though. I’ve ordered a new VC hoping that the one I originally purchased just has a defect. Is there anything else this could be? Please help.