There are two surfaces to seal on the valve cover gaskets. A smaller cover sits atop the larger valve cover. You must separate the two covers and clean all the surfaces very carefully to insure they are clean and dry before reassembly. The smaller cover attaches to the larger cover only with black silicone without a gasket. The larger cover attaches to the engine with a gasket. Many people only use the gasket to make the seal with the larger cover and have had good results. I placed a very thin coating of #2 Permatex ( non hardening) on the engine before installing the cover with the gasket in place on the cover. I have had no leaks over the past 6 years. I would recommend only using the OEM valve cover gasket. The smaller cover on top the main cover is for attaching the breather hose. Perhaps that hose is cracked or not sealing well. It is not a difficult job, but you must take your time, follow the directions on the black silicone and be certain you have the correct silicone as there are different types of the black available.