API SL/CI-4 SAE 15W-40 is a premium quality, heavy-duty multigrade oil for all season use in diesel and gasoline-powered or a mix of diesel and gasoline-powered equipment. It meets or exceeds the warranty and service requirements of virtually all diesel and gasoline engine manufacturers-for both newer and older engines. It is recommended for all on-highway and off-highway applications, especially where all season use is desired. These oils are especially effective at sustaining engine durability where Exhaust Gas Recirculation (EGR