Mobilgard HSD 15W-40 by Mobil is an extra high performance, multi-grade engine oil specifically formulated for severe service high-speed diesel engines in marine applications. Its advanced chemistry provides outstanding performance in both modern, demanding low-emission diesel engines and older diesel engines operating on low or high sulphur distillate fuel. Mobilgard HSD 15W-40 is approved or recommended by all the major marine high-speed diesel engine builders. Features and Benefits Mobilgard HSD 15W-40 combines a blend of high quality base stocks with a superior balanced additive system to provide exceptional control of oil thickening due to soot build-up and high temperatures, as well as outstanding resistance to oxidation, corrosion, and high temperature varnish deposits. When used as recommended, Mobilgard HSD 15W-40 diesel engine oil provides the following features and potential benefits: Outstanding thermal and oxidation stability Reduces formation of deposits and sludge b