Exceeds API Service Categories for heavy-duty-diesel engine oil: CK-4, CJ-4, CI-4, CI-4 Plus and older. SynShield® Durability Advantage 15W-40 Engine Oil is a premium advanced performance, synthetic plus, heavy-duty diesel engine oil formulated to provide maximum protection against wear, oxidation, deposit formation, soot contamination and aeration. SynShield® Durability Advantage 15W-40 Engine Oil provides excellent equipment durability and longevity even during harsh, extreme duty operating conditions. Using our proprietary friction modifiers, Micron Moly® and Penetro®, SynShield® Durability Advantage 15W-40 creates a slippery, tenacious shield that prevents metal-to-metal contact. This added layer of durability protection significantly reduces wear on bearings, rings, pistons, cylinders and valve trains. Our 15W-40 oil is suitable for use in emission compliant engines that utilize heavy exhaust gas recirculation (EGR) and exhaust after-treatment devices such as diesel particulate filters (DPFs) with or without diesel oxidation catalysts (DOCs) and selective catalytic reduction (SCR). SynShield® Durability Advantage 15W-40 Oil can also be used in low-emission certified diesel engines that are equipped with EGR, older non-EGR containing diesel engines, and off-highway diesel engines.