Kind of depends on whether you reseal only the small upper covers (Do IT YOURSELF) or both the smaller upper cover and the full lower covers. The small upper cover uses only RTV ultra black sealant, but the larger lower cover involves the purchase of a gasket and of course a little bit more work taken it off and putting it back on again. There are several threads here on the forum which detail the removal and resealing of the valve covers. Be aware that there are several different screw lengths and a very light torque on the screws: 10 N-m