About this item

• Product Overview

  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

  ^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 cleanliness^J 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

  ^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

  ^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.

• Technical Specifications
  Data Bulletin

  Data Bulletins

  Literature Sample

  AMSOIL Diesel Oil Comparison Chart

  Warranty

  WARRANTY

  SDS

  SDS (English)

  SDS (French)

  
  
  
• Product Reviews
  5 star rating

  Based on 109 reviews

  Based on 109 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    USE
    By  ANTHONY,  a  Verified Buyer  from  port colborne  on  May 08, 2026

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    excellent for my kubota
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Works
    By  DEREK,  a  Verified Buyer  from  Whitecourt  on  November 02, 2025

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    Love this product because in the end it saves me money
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Easiest oul change
    By  TYLER,  a  Verified Buyer  from  Alberta  on  June 29, 2025

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    Easy oil change perfect shipping
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Max -Duty Diesel Oil
    By  GLEN,  a  Verified Buyer  from  BC, Canada.  on  June 08, 2025

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    Good Product for my Ram Truck
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great product
    By  JOHN,  a  Verified Buyer  on  April 28, 2025

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    Been using am's oil for years. Great product.
    Bottom Line

    Yes, I would recommend this to a friend.
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    YES (0) NO (0)
  • 5 star rating
    Great Service
    By  DAVE,  a  Verified Buyer  from  V1W1V6  on  February 22, 2025

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    I accidentally ordered the wrong product and didn't realize it until after it was sent. Customer service told me how to return it and I reordered the product I needed.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Keeps old Running
    By  DALE,  a  Verified Buyer  from  Prince Edward County  on  November 20, 2024

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    I use it in my 1999 kubota B1700 runs like a top . It’s starts easy in cold weather and like top quality oil. Highly recommend AMSOIL products !
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    The only brand of engine oil I’ll use
    By  CHRISTOPHER,  a  Verified Buyer  from  Canada  on  November 19, 2024

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    As the title states. We’ve all invested hard earned money in our vehicles, doesn’t make sense to mistreat them.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    2022 F250 6.7 power stroke
    By  Kilo,  a  Verified Buyer  from  Virginia   on  March 03, 2024

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    After I started using this oil in my 6.7 powerstoke I have noticed a 1 mpg gain and smoother idling. This engine oil is the best stuff on earth in my opinion and with a $70,000 truck this is the only oil it deserves. You put good in and good will come out.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    Excellent product
    By  MICHEL,  a  Verified Buyer  on  February 25, 2024

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    The best
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)

• Highlights

  • 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

• Returns

  We offer easy returns for customers. If your product is unused and unopened, you may return it within 30 days for a full refund of the purchase price. View full AMSOIL Return Policy.

• Payments

  We accept Visa, Mastercard, American Express, Discover and PayPal, and provide secure checkout and encrypted payment processing.

• Product Overview

  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

  ^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 cleanliness^J 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

  ^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

  ^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.

• Technical Specifications
  Data Bulletin

  Data Bulletins

  Literature Sample

  AMSOIL Diesel Oil Comparison Chart

  Warranty

  WARRANTY

  SDS

  SDS (English)

  SDS (French)

  
  
  
• Product Reviews
  5 star rating

  Based on 109 reviews

  Based on 109 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    USE
    By  ANTHONY,  a  Verified Buyer  from  port colborne  on  May 08, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    excellent for my kubota
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Works
    By  DEREK,  a  Verified Buyer  from  Whitecourt  on  November 02, 2025

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Love this product because in the end it saves me money
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Easiest oul change
    By  TYLER,  a  Verified Buyer  from  Alberta  on  June 29, 2025

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Easy oil change perfect shipping
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Max -Duty Diesel Oil
    By  GLEN,  a  Verified Buyer  from  BC, Canada.  on  June 08, 2025

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Good Product for my Ram Truck
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Great product
    By  JOHN,  a  Verified Buyer  on  April 28, 2025

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    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Been using am's oil for years. Great product.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Great Service
    By  DAVE,  a  Verified Buyer  from  V1W1V6  on  February 22, 2025

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I accidentally ordered the wrong product and didn't realize it until after it was sent. Customer service told me how to return it and I reordered the product I needed.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Keeps old Running
    By  DALE,  a  Verified Buyer  from  Prince Edward County  on  November 20, 2024

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I use it in my 1999 kubota B1700 runs like a top . It’s starts easy in cold weather and like top quality oil. Highly recommend AMSOIL products !
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    The only brand of engine oil I’ll use
    By  CHRISTOPHER,  a  Verified Buyer  from  Canada  on  November 19, 2024

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    As the title states. We’ve all invested hard earned money in our vehicles, doesn’t make sense to mistreat them.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    2022 F250 6.7 power stroke
    By  Kilo,  a  Verified Buyer  from  Virginia   on  March 03, 2024

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    After I started using this oil in my 6.7 powerstoke I have noticed a 1 mpg gain and smoother idling. This engine oil is the best stuff on earth in my opinion and with a $70,000 truck this is the only oil it deserves. You put good in and good will come out.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    Excellent product
    By  MICHEL,  a  Verified Buyer  on  February 25, 2024

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    The best
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)