Look on the surface of the head for the four locations where the silicone has been applied. These are the four right angles where the camshafts penetrate on the passenger side. The area on the front bank exhaust camshaft that is filled by the semicircular plug in the gasket should have the entire portion covered with a film of silicone. Do not use the silicone on any other areas of the seal. Let the rubber do its job. You will have to remove the old silicone and apply a new oxygen sensor safe silicone (RTV) to these locations. I have used Permatex Ultra Gray that is available at any auto parts store in the sealants section.