SAE 15W-40 Synthetic Heavy Duty Diesel and Marine Motor Oil

Premium Protection for Severe-Service Diesels

AMSOIL Synthetic Heavy Duty Diesel and Marine Motor Oil is a premium diesel oil that provides excellent performance in all types of diesel engines without exhaust aftertreatment systems, where highly effective control of wear and deposits is vital. Engineered with heavy-duty dispersant/detergent additives, its Total Base Number (TBN) of 12 neutralizes acids and controls soot thickening from exhaust gas recirculation (EGR) and blow-by to protect against corrosion, cylinder bore polishing (wear), varnish and sludge deposits. AMSOIL 15W-40 Diesel Oil resists heat and breakdown better than conventional petroleum oils for long-lasting performance and protection.

Extends Drain Intervals

AMSOIL Synthetic Heavy Duty Diesel with Marine Oil can extend drain intervals far beyond those recommended for conventional petroleum oils. Its unique synthetic formulation and long-drain additive chemistry deliver maximum engine protection, cleanliness and performance over extended drain intervals, reducing vehicle maintenance and waste-oil disposal costs.

Controls Soot and Wear

AMSOIL Synthetic Heavy Duty Diesel with Marine Oil is heavily fortified with detergent/dispersant additives and is naturally resistant to soot. It is designed to keep soot particles suspended independently and prevent them from aggregating to form larger, wear-causing particles. Viscosity increase is minimized and soot-related wear is reduced.

SAE 15W 40 Heavy Duty Diesel and Marine Oil Gallon AME1G scaled
SAE 15W-40 Heavy-Duty Diesel with Marine Oil

• Recommended for applications specifying API CI-4+ and prior specifications
• Controls soot and wear
• Reduces oil consumption and emissions
• Delivers maximum engine protection over extended drain intervals
• Provides outstanding protection and performance in temperature extremes
• Try Signature Series Max-Duty 15W-40 for a serious upgrade


Reduces Oil Consumption and Emissions

AMSOIL Synthetic Heavy Duty Diesel with Marine Motor Oil has lower volatility than conventional petroleum oils. Oil consumption and emissions are minimized due to less vapor passing into the combustion chamber. Lower volatility helps AMSOIL 15W-40 Diesel Oil retain its viscosity after high-temperature service for continued dependable protection.

Excellent Cold-Flow Properties

AMSOIL Synthetic Heavy Duty Diesel with Marine Oil eases cold-weather starting and provides vital startup lubrication to help prevent engine wear. It outperforms conventional 15W-40 petroleum oils and minimizes the impact of cold-weather operation.

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