AMSOIL Signature Series 0W-40 100% Synthetic Motor OilA New Level of Motor Oil Technology 75% more engine protection against horsepower loss and wear. 1 50% more cleaning power vs. AMSOIL OE Motor Oil Protects turbochargers 72% better than required2 by the GM dexos1 Gen 2 specification. 28% more acid neutralizing power than Mobil 1. 3 Trusted by professional engine builders Guaranteed protection for up to 25,000 miles or 1 year 1Based on independent testing of AMSOIL Signature Series 0W 20 using the ASTM