AMSOIL’s new Premium API CJ-4 Synthetic 15W-40 Diesel Oil is emission-compliant and backward compatible. Its heavy-duty detergent/dispersant additives and high 10.4 TBN control soot thickening from exhaust gas recirculation and blow-by to protect against corrosion, cylinder bore polishing and varnish/sludge deposits. It is engineered for a wide range of applications and recommended for extended service life in engines that are unmodified and in good operating condition.