Goodyear Performance Max Heavy Duty Diesel Engine Oil, SAE 15W-40 - API CK-4. Heavy Duty Diesel Engine Oil – Designed for modern and legacy diesel engines requiring SAE 15W-40 lubrication. Performance Max CK-4 diesel engine oil is designed for use in model year 2017 and newer heavy-duty diesel engines while remaining fully backward compatible with engines requiring earlier API C service classifications.
