15W-40 Diesel Engine Premium Full Synthetic Oil (10TBN) improves lubrication, fuel economy and extends drain Intervals in ultra-low emission diesel Engines. This is the best choice diesel engine oil for years 2007 and newer, heavy-duty and pickup truck diesel engines requiring API CJ-4 emission-quality oil standards. This diesel oil delivers extraordinary lubrication in all diesel engines in commercial, fleet and personal vehicle applications. OnGuard 15W-40 Diesel Engine Premium Full Synthetic Oil represents the current state of the art in lubricant technology. By blending performance additives with ultra-high quality synthetic base stocks, OnGuard 15W-40 Motor Oil’s superior formulation provides acid control, deposit control, and protects against engine wear, providing enhanced engine performance, and extended drain intervals. It meets the specification for diesel and gasoline engines requiring API classification CJ-4, CI-4 Plus, CI-4/SN oil. It is also suitable for use in CAT ECF-1-a, ECF-3, Mack EO-O Premium Plus, and Cummins CES 20081 applications.