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AMSOIL Signature Series 5W-40 100% Synthetic Max-Duty Diesel Oil

Product code : DEOQT-EA

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

     

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

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AMSOIL Signature Series 5W-40 100% Synthetic Max-Duty Diesel Oil



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.

AMSOIL Signature Series 5W-40 100% Synthetic Max-Duty Diesel Oil

Data Bulletin

Warranty

SDS



AMSOIL Signature Series 5W-40 100% Synthetic Max-Duty Diesel Oil

  • 5 star rating
    Great stuff!
    By  CHARLIE,  a  Verified Buyer  on  January 14, 2025
    Love this oil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Newer Diesels
    By  CURTIS,  a  Verified Buyer  on  January 09, 2025
    I just bought a newer diesel 5th wheel hauler to replace our aged 2002 Duramax. The old truck only used Amsoil 15w-40 Marine Diesel Oil. The new truck takes 5w-40 full synthetic or 10w-30. Since the marine grade doesn’t come in 5w-40, I used the signature series. Looking forward to many years with this new truck using Amsoil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    AMSOIL Signature 5W-40 Synthetic Max-Duty Diesel Oil
    By  JOHN,  a  Verified Buyer  from  KS  on  January 08, 2025
    I began using the Signature 5W-40 Synthetic Max-Duty Diesel Oil in my 2024 New Ford F-350 with the new HO Diesel engine this past fall. I manage a large farm in Central KS and work in very extreme conditions. I’ve been more than happy with it’s performance and trust AMSOIL superior products will protect my engine for a long, long time.
    Bottom Line
    Yes, I would recommend this to a friend.
    Was this review helpful?
  • 5 star rating
    Premium oil
    By  JEFF,  a  Verified Buyer  from  AZ  on  January 06, 2025
    Arrived quick. Great customer service.
    Bottom Line
    Yes, I would recommend this to a friend.
    Was this review helpful?
  • 5 star rating
    EXCELLENT OIL
    By  HEATH,  a  Verified Buyer  from  Colorado  on  January 04, 2025
    Can't get any better than Amsoil!!
    Bottom Line
    Yes, I would recommend this to a friend.
    Was this review helpful?
  • 5 star rating
    Amsoil quality
    By  AARON,  a  Verified Buyer  on  January 03, 2025
    I have been using AMSOIL for years now and absolutely love it! I use the full synthetic and won't ever switch.
    Bottom Line
    Yes, I would recommend this to a friend.
    Was this review helpful?
  • 5 star rating
    Works great
    By  JEFF C,  a  Verified Buyer  from  Lexington Kentucky   on  January 03, 2025
    Perfect thank you
    Bottom Line
    Yes, I would recommend this to a friend.
    Was this review helpful?
  • 5 star rating
    Perfect Lube for Cold Midwest Winters
    By  Jim,  a  Verified Buyer  from  Indiana  on  January 03, 2025
    I've been using AMSOIL 5W40 Diesel Oil in my John Deere 1025r for more than 10 years. I store the tractor outside under cover without benefit of a block heater. Even on the coldest, below zero mornings, the tractor starts right up with just one cycle of the glow plugs. Year round protection in all temperature extremes is why I've been an AMSOIL fan for more than 25 years.
    Bottom Line
    Yes, I would recommend this to a friend.
    Was this review helpful?
  • 5 star rating
    Liquid gold
    By  JOHN,  a  Verified Buyer  from  Florida  on  December 31, 2024
    All Amsoil products are great but especially the quality of their signature line. I own a Ram 3500 (non dually) with the Cummins 6.7L and my engine runs whisper quiet with it. I can always tell quality oil with how long the engine takes to warm up. Not only that but the viscosity lasts longer than other oils. I'm something of a nerd to checking how thin the oil is when it drains and I always feel like I've changed my oil too soon. A great product hands down.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Good
    By  LUIS,  a  Verified Buyer  on  December 31, 2024
    Best oil ever
    Bottom Line
    Yes, I would recommend this to a friend.
    Was this review helpful?