Kendall super-d xA (exhaust advantage) Diesel engine oil with liquid titanium protection additive is a premium quality, part-synthetic api ck-4 engine oil developed for use in four-stroke cycle Diesel engines designed to meet 2007 and later EPA on-highway exhaust emissions standards. It is specially formulated for compatibility with exhaust After treatment systems using Diesel particulate filters (DPF), Diesel oxidation catalysts (doc) and/or selective catalytic reduction (SCR). it is back serviceable for use in pre-2007 Diesel engines.