Shell Rotella 550019921 T6 Full Synthetic Heavy Duty Engine Oil 5W-40, 1 Gallon, 128. Fluid_Ounces Better fuel economy - compared to 15W-40 oils Rotella offers enhanced fuel economy capability of 1.5% without compromising engine protection or durability Improved wear performance - provides a significantly increased level of protection against harmful engine wear when compared to previous generation API CJ-4 engine oils Improved deposit control - advanced multi-functional dispersant additives in combination with synthetic base oils provide an enhanced level of protection against the effects of soot, dirt and other contaminants Emissions system compatibility - advanced low-ash formulation helps control blocking of or poisoning of exhaust after-treatment devices, helping maintain vehicle emission compliance and engine fuel efficiency Improved heat resistance - resists breakdown by heat to provide continuous protection throughout the service interval Shell Rotella T6 full synthetic, heavy duty, oil features an advanced multi-functional, low-ash additive technology in a synthetic base oil designed to provide highly responsive protection that continuously adapts to your driving conditions Rotella T6 is formulated with reduced levels of ash, phosphorous and sulfur to help maintain the efficiency of the latest vehicle-emissions technologies Shell Rotella T6 5W-40 provides excellent low-temperature flow, even at -30 degrees Fahrenheit Shell Rotella T6 5W-40 provides unsurpassed protection against shear-stability degradation, compared to the leading competitive API CJ-4 5W-40 products