Mobil Delvac Modern 15W-40 SD (Super Defense) is a high-performance heavy-duty diesel engine oil designed to provide reliable lubrication and protection for both modern and older diesel engines. Its advanced formulation helps control soot-related oil thickening, oxidation, corrosion, sludge, and high-temperature deposits, supporting cleaner operation and longer engine life. It is suitable for demanding on-road and off-road applications, including trucks, buses, construction equipment, agricultural machinery, and mixed fleets.