AMSOIL 15W-40 Synthetic Diesel Oil is the premium choice for API CJ-4 emission-quality diesel oil required by model-year 2007 and newer diesel engines, as well as older diesel applications (including those equipped with turbochargers). It delivers extraordinary lubrication in diesel engines found in commercial, fleet and personal vehicles. Formulated with the latest additive and synthetic base oil technology, AMSOIL Premium 15W-40 Synthetic Diesel Oil exceeds the higher performance demands of modern engines. It withstands the stress of heat, soot and acids to help prevent deposits, corrosion and wear.