Best Selling Amsoil Max-Duty Synthetic Diesel Oil 15W-40

Amsoil's 15W-40 Max Duty Signature Series 100% synthetic diesel oil

AMSOIL Signature Series Max-Duty Synthetic 15W-40 Diesel Oil is the premium of all AMSOIL Diesel Oils

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This is the one – Signature Series Max-Duty 100% Synthetic Diesel Oil 15W-40

If you push your truck beyond it’s design limits you’ll find this will keep up!

Maximum-duty protection for your hardest-working diesel engines

Signature Series Max-Duty Synthetic Diesel Oil 15W-40Maximum 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.

Sold in quarts, gallons, 2.5-gallon jug and cases of each. Drums and larger sizes are also available for added savings.

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Viscosity Control

Using top-tier synthetic base oils, AMSOIL Signature Series Max-Duty 15W-40 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 retain its viscosity after high-temperature service for maximum engine protection and efficiency.

Printable Product Data Bulletin

Download PDFProduct Datasheet

 

Excels in Extreme Temperatures

AMSOIL Signature Series Max-Duty 15W-40 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 for easier 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, making it excellent for use in both hot-operating engines and cold-weather starting extremes.

Minimizes Oil Consumption

AMSOIL 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.

 

Reduced oil consumption is a hallmark asset with AMSOIL saving you in operational costs including reduced DEF usage.

 

APPLICATIONS

Use in diesel engines and, where appropriate, gasoline engines requiring any of the following specifications:

  • API CK-4/SN, CJ-4, CI-4+, CF
  • Volvo VDS4.5, VDS4, VDS3
  • Mack EOS-4.5, EO-O
  • Renault RLD-4, RLD-3
  • Cummins CES20086, CES20081
  • Caterpillar ECF-2, ECF-3, ECF-1-a
  • DDC 93K218, 93K215, 93K214
  • DFS 93K222
  • ACEA E9, E7
  • MB 228.31
  • MAN 3575
  • MTU Type 2.1, II, I
  • JASO DH-2
  • Deutz DQC III-10LA
  • Scania LA-2
  • Chrysler MS 10902
  • Ford WSS-M2C171-F1

COMPATIBILITY

AMSOIL Signature Series Max-Duty Synthetic Diesel Oil is compatible with other conventional and synthetic engine oils. Mixing AMSOIL diesel oils with other oils, however, will shorten the oil’s life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

Aftermarket oil additives are not recommended for use with AMSOIL synthetic diesel oils.

SERVICE LIFE

Diesel Engine Service Life
Heavy-Duty On-/Off-Road: Three times (3X) OEM1 recommendation, not to exceed 60,000 miles/600 hours or one year, whichever comes first.

Turbodiesel Pickup: Two times (2X) OEM1 recommendation, not to exceed 25,000 miles or one year, whichever comes first.

Gasoline Engine Service Life
Two times (2X) OEM1 recommendation, not to exceed 15,000 miles or one year, whichever comes first.

Drain intervals may be extended further with oil analysis.

1Refer to your owner’s manual for OEM drain interval recommendations and guidelines for severe and normal service.

Note: Extended drain intervals are not recommended for performance-modified engines, when using biofuels containing more than 10 percent ethanol or 15 percent biodiesel (B15) or for 2007-2009 Caterpillar* C13 and C15 on-highway engines. Extend drain intervals beyond OEM recommendations in these instances only with oil analysis. Note: 2007-2010 Dodge**, Ford** and GM** turbodiesel pickups are also not recommended for extended drain intervals when using DHD.

AMSOIL PRODUCT WARRANTY

AMSOIL products are backed by a Limited Liability Warranty. For complete information visit AMSOIL Warranty Information

* All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are developed by AMSOIL for use in the applications shown.

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Diesel – Sig Series Customer Reviews

Best diesel oil on the market by a mile.

By  RYAN,  a  Verified Buyer  from  Lookout Mountain Georgia   on March 15, 2025
Run 35k changes on the Cummins running this a AMSOIL ea080 and the Amsoil large bypass system. Last truck got 1.3 million miles on all original Cummins 6.7 engine.

15-40 diesel oil

By TONY,  a  Verified Buyer on  March 14, 2025
I have used this oil for the last 10 years in a 2015 Duramax. I work the truck every day and have 209k miles on the truck. The truck doesn’t use any oil between its 7500 mile oil changes and still runs like new. I recommend giving it a try.

Amsoil oil

By  MICHAEL,  a  Verified Buyer  from  Texas  on  March 14, 2025
I used Amsoil in the 1980’s back then you had to know someone that sold it. Now we can order it online, it’s costly but I use it until I reach 12000-15000 miles which is usually about a year and a half. I trust the brand. I keep a spare case on hand.

Great oil used in my l5p Duramax

By  ROBERT,  a  Verified Buyer  from  Ohio  on  March 11, 2025
Great oil , no complaints , it even got rid of the classic Duramax type writer tick ! I’ll never use another oil in it now that I’ve used this

Due for oil change

By  JONITHAN,  a  Verified Buyer  on  March 10, 2025
Always a pleasure Pays to be a member for discounts My goto products

Best Product-Best customer service

By  JUSTIN,  a  Verified Buyer  from  Bellefonte PA   on  March 07, 2025
I’ve been using Amsoil almost 30 years and has certainly proven to me that it is everything they say it is..I certainly recomend it. Ive just started ordering directly through amsoil for the 25% discounted price and one of my orders had 2 quarts damaged, took a pic and emailed it and within hours they responded and sent new ones immediately. Couldnt be happier with service! ⭐️⭐️⭐️⭐️⭐️💯