Formerly known as Shell Rotella T Triple Protection, Shell Rotella T4 Triple Protection Heavy Duty Diesel Engine Oil is the most technically advanced Shell Rotella formulation ever. This 15W-40 motor oil uses advanced additive technology to protect under the most severe engine conditions found in modern, low-emission engines and older hard-working diesel engines. It effectively sustains emissions control system durability where diesel particulate filters and after-treatment systems are used. Plus, it provides enhanced protection against viscosity loss due to shear and improved oil aeration compared to the previous formulation.