I think you meant to say, valve cover gasket and not head gasket. The valve cover gasket should not be too hard. Make sure you clean the area and make sure the little hole in the back upper area on top of the number 4 spark plug is clear and clean. This hole allows water to exit in case it gets on top of your engine and in the spark plug compartment. When you check the area, check the coils and make sure they are not cracked in the plug area. Be careful not to drop the resistor located in the rubber cover. If they are cracked, change them, I kept them there for a while and it backfired on me far from home and far from a dealer of autoparts store.