Been smelling burning oil for about a week now; never really had a chance to look at it, but I was assuming maybe I need to replace the valve cover gaskets; my car has 78k on it. Today I check my oil dipstick, and it reads full and nothing looks unusual. When I take my oil cap off, there is a white creamy substance on the inside of it and also on the filler neck too. Any advice or help would be greatly appreciated.