Delo® 400 SDE SAE 15W-40 with ISOSYN® Advanced Technology is a heavy duty engine oil recommended for naturally aspirated and turbocharged four-stroke diesel engines and four-stroke gasoline engines in which the API CK-4 or SN service category and SAE 15W-40 viscosity grade are recommended. Delo 400 SDE 15W-40 is also backwards compatible with diesel engines in which the API CJ-4, CI-4, CI-4 Plus and CH4 service categories are recommended.