Back

Close Icon

Main Menu

Your order may take longer than normal to arrive. We are experiencing extremely high demand and freight carriers are experiencing delays nationwide.

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

Product code : DEOQTC-EA

Outstanding extreme-pressure protection
Delivers 6X more wear protection1
Maintains proper viscosity (thickness)
Minimizes oil consumption
Maximizes fuel efficiency
Excels in extreme temperatures

1Based on third-party testing in the Detroit Diesel DD13 Scuffing Test for specification DFS 93K222 using 5W-30 as worst-case representation

Outstanding extreme-pressure protection
Delivers 6X more wear protection1
Maintains proper viscosity (thickness)
Minimizes oil consumption
Maximizes fuel efficiency
Excels in extreme temperatures

1Based on third-party testing in the Detroit Diesel DD13 Scuffing Test for specification DFS 93K222 using 5W-30 as worst-case representation

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



Developed to protect the horsepower diesel enthusiasts crave and extend the life of hard-working commercial equipment in the most severe conditions. Signature Series synthetic technology delivers max-duty protection in on- and off-road applications.

See the Product Data Bulletin for full details.

MAXIMUM ENGINE PROTECTION

  • Delivers 6X more wear protection,1 delivering extra protection so you can push your diesel with peace of mind
  • Provides long-lasting wear protection, keeping cylinder liners looking like new2
  • Delivers up to 60 percent better turbo cleanliness3
  • Withstands the extra demands you place on the turbo when pulling heavy loads or updating the tune for maximum horsepower
  • Provides up to 2X better rust protection4

1Based on third-party testing in the Detroit Diesel DD13 Scuffing Test for specification DFS 93K222 using 5W-30 as worst-case representation
2Based on independent testing of AMSOIL 5W-30 Signature Series Max-Duty Synthetic Diesel Oil and a leading conventional 15W-40 diesel oil using the Detroit Diesel* DD13 Scuffing test for specification DFS 93K222.
3Based on specification standards of CAT C13 2nd Ring Top Land Carbon testing
4Based on industry standard testing using the NMMA FC-W Rust Test.


Delivers More Wear Protection

Third-party testing shows Signature Series Max-Duty Synthetic Diesel Oil delivers 6X more protection against wear than required by Detroit Diesel’s* standard.II

IIBased on third-party testing in the Detroit Diesel DD13 Scuffing Test for specification DFS 93K222 using 5W-30 as worst-case representation.
*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.


AMSOIL Fights Wear

AMSOIL delivers powerful engine protection. How good is it? In third-party testing compared to a leading brand, AMSOIL provided long-lasting wear protection, keeping cylinder liners looking like new.DD

AMSOIL Fights Wear – AMSOIL delivers powerful engine protection. How good is it? In third-party testing compared to a leading brand, AMSOIL provided long-lasting wear protection, keeping cylinder liners looking like new.

DDBased on third-party testing of AMSOIL 5W-30 Signature Series Max-Duty Synthetic Diesel Oil and a leading conventional 15W-40 diesel oil using the Detroit Diesel* DD13 Scuffing test for specification DFS 93K222.
*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.


Keeps Turbos Clean

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

JBased on specification standards of CAT C13 2nd Ring Top Land Carbon testing


Protects Against Rust

Provides up to 2X better rust protection.K Protects Against Rust – Provides up to 2X better rust protection.

KBased on industry standard testing using the NMMA FC-W Rust Test.


VISCOSITY CONTROL

  • Resists oxidation and the thickening effects of soot contamination
  • Retains viscosity after high-temperature service for maximum engine protection and efficiency
  • Provides up to 76 percent less oil consumption5

5Than required by the API CK-4 standard in the Caterpillar-1N oil consumption test


Reduces Oil Consumption

Signature Series Max-Duty Synthetic Diesel Oil provides up to 76% less oil consumption.L

Reduces Oil Consumption – Signature Series Max-Duty Synthetic Diesel Oil provides up to 76% less oil consumption.

LThan required by the API CK-4 standard in the Caterpillar-1N oil consumption test.


EXCELS IN EXTREME TEMPERATURES

  • 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.

See the Product Data Bulletin for full details.

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



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

  • 5
    Nice for Duramax
    By  BOBBY,  a  Verified Buyer  on  May 01, 2021

    Describe the issue

    Actually added a couple of mpg on my 2003 Duramax. Like the product.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Perfect application
    By  LESTER,  a  Verified Buyer  from  Brighton TN  on  April 25, 2021

    Describe the issue

    Even the local Ford place recommends and will service my F250 with Amsoil
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Oil review
    By  STEVE,  a  Verified Buyer  from  Munford TN  on  April 24, 2021

    Describe the issue

    Best oil on the market love it
    Bottom Line
    Yes, I would recommend this to a friend.
  • 4
    Good product
    By  NEWTON,  a  Verified Buyer  from  Weatherford tx   on  April 24, 2021

    Describe the issue

    Good oil, have over 7000 miles and still clean for a diesel.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Best oil I've tried
    By  TERRY,  a  Verified Buyer  from  IA  on  April 23, 2021

    Describe the issue

    BETTER COLD STARTS AND WARM WEATHER PRESSURE THAN SYN ROTELLA I CAN'T THINK OF ONE THING I DONT LIKE ABOUT THIS OIL
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Best oil for your diesel.
    By  MILES,  a  Verified Buyer  on  April 22, 2021

    Describe the issue

    As always amsoil performs great. Cold starts are much easier, and the oil flows much more readily based on oil pressure readings. I’ve ran amsoil products in everything from motorcycles to diesel trucks and can’t recommend it enough.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great product
    By  BILLY,  a  Verified Buyer  on  April 19, 2021

    Describe the issue

    Absolutely the best oil I’ve ever used.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great product fast shipping
    By  ERIC,  a  Verified Buyer  from  Pennsylvania   on  April 19, 2021

    Describe the issue

    Love this product
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Amsoil Products
    By  LAURENCE,  a  Verified Buyer  on  April 18, 2021

    Describe the issue

    I have been using Amsoil products for 30 years. Need I say more???
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great Products
    By  DOUG,  a  Verified Buyer  from  Lethbridge   on  April 17, 2021

    Describe the issue

    I love being able to order direct from amsoil . It is extremely convenient and the quality of the products is second to none.
    Bottom Line
    Yes, I would recommend this to a friend.