Protect your investment in diesel power and confidently extend drain intervals with our top-grade synthetic diesel oil. AMSOIL Signature Series Max-Duty Synthetic Diesel Oil delivers 6X more wear protection,* giving your diesel the extra protection it deserves. Advanced synthetic technology provides excellent viscosity control and outstanding extreme-temperature performance, while minimizing oil consumption. The result: protection that’s boosted to the max.

Maximum Engine Protection

Wear on rings and cylinder liners leads to increased oil consumption and loss of compression, resulting in reduced horsepower and fuel economy. Third-party testing shows Signature Series Max-Duty delivers 6X more wear protection than required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222, delivering extra protection so you can push your diesel with peace of mind.

Viscosity Control

Using top-tier synthetic base oils, Signature Series Max-Duty is naturally resistant to oxidation and the thickening effects of soot contamination. That, along with boosted detergent/dispersant additives, keeps soot particles suspended independently, helping prevent the formation of larger, wear-causing particles. Viscosity increase is minimized and soot-related wear is controlled. Lower volatility also helps Signature Series Max-Duty Diesel Oil retain its viscosity after high-temperature service for maximum engine protection and efficiency.

Excels in Extreme Temperatures

Signature Series Max-Duty Synthetic Diesel Oil resists thermal (heat) breakdown better than conventional and competing synthetic diesel oils. Unlike conventional oils, Signature Series contains no wax, staying fluid in sub-zero temperatures foreasier starting, improved oil flow and reduced wear. Signature Series 0W-40 (DZF) has a broad viscosity range that offers 4X better cold-cranking ability than a 15W-40 oil in the ASTM D5293 cold-cranking viscosity test, making it excellent for use in both hot-operating engines and cold-weather starting extremes.

Minimizes Oil Consumption

Signature Series Max-Duty has a low rate of volatility (burn-off), reducing oil consumption during operation and passing less oil vapor into the combustion chamber. It provides up to 76 percent less oil consumption than required by the API CK-4 standard in the Caterpillar-1N oil consumption test.

Keeps Turbos Clean

AMSOIL Signature Series Max-Duty Synthetic Diesel Oil provides protection boosted to the max, delivering up to 60% better turbo cleanliness and withstanding the extra demands you place on the turbo when pulling heavy
loads or updating the tune for maximum horsepower.