Maximum protection to help extend engine life. 6x better wear protection (As measured in the latest sequence IVA test). 1.3x better sludge protection (as measured in sequence VH sludge test vs. API SP limits). American petroleum institute certified for gasoline engines. The superior protection of GTX Full Synthetic helps fight the impact of heat, short trips and traffic that can all lead to sludge, potentially shortening engine life. It cleans away old sludge (when tested in engines with high level of sludge) and protects against new sludge formation. It also dramatically reduces engine wear - 6x better than the industry standard. Castrol GTX Full Synthetic helps extend engine life with: Superior sludge cleaning and protection against new formation. Superior wear protection on critical engine parts. Full synthetic formula that provides thermal and oxidation stability. Superior level of protection against viscosity breakdown. Exceeds: API SP/SN PLUS/SN. ILSAC GF-6. Meets ford WSS-M2C945-B1. Meets ford WSS-M2C960-A1. Don't pollute. Conserve resources; return used oil to collection centers.