Indestructible Max-Duty Synthetic Diesel 5W-40

Amsoil's 5W-40 Max Duty Signature Series diesel oil

When someone says You gotta use AMSOIL diesel oils this is the one. 5W-40 replaces 15W-40 in newer trucks as well. Improves MPG.

SKU: DEO Category:

Signature Series Max-Duty Synthetic Diesel Oil 5W-40

Maximum-duty protection for your hardest-working diesel engines

Signature Series Max-Duty Synthetic Diesel Oil 5W-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. Independent testing shows AMSOIL Signature Series Max-Duty 5W-40 delivers 6X more wear protection than required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222, delivering the security of providing your diesel the extra protection it deserves.

Excellent pricing when you select the Preferred Customer options and in case prices.

Buy & Price

The 5W-40 is sold in quarts, gallons, 2.5 gallon jug and cases of each. Drums and larger sizes are also available for added savings.

 

Beyond Industry Viscosity Control

Using top-tier synthetic base oils, AMSOIL 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 retain its viscosity after high-temperature service for maximum engine protection and efficiency.

 

Product Data Bulletin for all the Signature Series Diesel line

Download PDFProduct Datasheet

 

Match the right lubricants to your vehicles

Match Your VehicleProduct Guides

 

Excels in Extreme Temperatures

AMSOIL Signature Series Max-Duty Synthetic Diesel Oil resists thermal (heat) breakdown better than conventional and competing synthetic diesel oils.

  • Provides outstanding protection and performance in hot and cold temperature extremes
  • Resists thermal (heat) breakdown better than conventional and competing synthetic diesel oils.
  • Stays fluid in sub-zero temperatures for easier starting, improved oil flow and reduced wear.
  • The DEO 5W-40 is a year-round formulation for all climates. No need to change to a 15W-50 in the summer (as I’m often asked). None at all!

 

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.

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
  • Allison TES439
  • 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

Signature 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.

HEALTH & SAFETY

This product is not expected to cause health concerns when used for the intended application and according to the recommendations in the Safety Data Sheet (SDS). USA and Canada (M)SDS are available upon request at 715-392-7101 or on the AMSOIL Website. Keep Out of Reach of Children. Don’t pollute. Return used oil to collection centers.

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

 

6.7 Powerstroke

By ROBERT,  a  Verified Buyer  from  St. Augustine Florida on  March 02, 2025
I use Amsoil 5W 40 Signature Series in my 2016 F350 with the 6.7 Powerstroke. I have reviewed several different brands and Amsoil is always in the top. It is also very competitively priced compared to Motorcraft Full Synthetic 5W-40. I appreciate the fact I can have it delivered right to my door and not have to go to the dealership and hope they have Synthetic in stock.

Performance and Durability

By PETER,  a  Verified Buyer from  NJ on  February 18, 2025
Excellent product for its wear protection. Zero oil consumption. No worries when you occasionally go past recommended oil change intervals. Oil temperatures stay lower under higher loads. 2.5 gallon container size is an added plus.

best oil for longevity

By MARK,  a  Verified Buyer from  Florida  on  February 15, 2025
In my 2004 dodge diesel, which was purchased new, I have used Amsoil oil and filters since its first oil change, about 490,000 miles ago, with no engine repairs required. I change the oil and filter once a year or about 25,000 miles. Highly recommend. I use Amsoil products in everything that needs oil, Tahoe, 4-wheeler, lawnmower, outboard motor, etc.

AMAZING customer service!!

By ROBERT,  a  Verified Buyer from  Texas on  February 14, 2025
My Amsoil dealer ALWAYS gets my products to me way faster than expected!! The brand speaks for itself, so having the added excellent service keeps me coming back every time!!!