Valvoline Diesel Extra 15W-40 is a premium diesel engine oil suitable for heavy duty diesel engines in trucks, buses and off-road machinery with Exhaust Gas Recirculation (EGR). Diesel Extra 15W-40 is specifically formulated for older mixed fleet applications where heavy duty European, American and Japanese diesel engines are used. its formulation includes advanced dispersants for exceptional soot control, engine durability and engine cleanliness.