Maximize engine durability. Supreme 9000 Full Synthetic Diesel Engine Oil 5w40 is engineered with the finest quality of PAO synthetic base oils, two proven friction modifiers, an advanced performance additive package and a viscosity index improver. This unique blend creates a premium, longer lasting oil that withstands a higher heat range – up to 300° – than conventional oil. Schaeffer's Fully Synthetic 5W40 Oil significantly reduces friction and provides superior protection against damaging metal-to-metal contact. Schaeffer's 5W40 Full Synthetic Engine Oil keeps diesel engines exceptionally clean and free from oil residue and sludge. Supreme 9000 Full Synthetic 5W40 Oil exceeds the current requirements for API CJ-4 and is versatile for use in 2007 and newer emission compliant engines utilizing heavy EGR and exhaust after-treatment devices. Schaeffer's 5W40 diesel oil is recommended for use in older, non-EGR and off-highway diesel engines and mixed fleet applications.