Royal Purple All-In-One Diesel Additive Max-Tane is a specially blended diesel performance additive for light, medium, and heavy duty diesel engines. Its year-round formula works with all grades and types of diesel fuel, including #1, #2, biodiesel, and ultra-low sulfur diesel (ULSD). Max-Tane solves most problems related to today's HPCR (High-Pressure Common Rail) diesel injection systems. It is also safe for all diesel exhaust emissions equipment, including catalytic converters and particulate filters (do not pour Max-Tane into diesel exhaust fluid).