HEAVY DUTY (HD) 15W-40 Synthetic Blend Diesel Engine Oil is a superior quality oil that is formulated to provide greater protection than a standard 15W-40. HD is formulated with premium quality based oils and additives for engines operating under severe service and a wide range of climate conditions. It is suitable for virtually all modern low-emission heavy duty engines, especially those with exhaust after-treatment devices meeting Euro 4, 5 emissions requirements. Because it is a blend of premium syn-blend base oils and selected additives, HD 15W-40 is designed to give excellent performance in all EGR engines. This engine oil contains an effective additive system, which is compatible with and keeps all EGR engines highly clean.  HD 15W-40 exceeds API CI – 4 / SL requirements.