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

  
  
  
• Product Reviews
  4.9 star rating

  Based on 1,585 reviews

  Based on 1,585 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    Extended Oil Life
    By  Jerry,  a  Verified Buyer  from  NE  on  September 17, 2026

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    I have a 21' Ram 2500 Mega Cab W/6.7 Ltr motor. I've used this oil since it's first oil change. 10,000 mile oil changes are recommended and I usually follow that recommendation consistently. This last change, I've monitored the trucks 'oil life' percentage gauge as I'm in the middle of a move and the truck is towing a 24'x8.5' enclosed trailer full of household stuff. I reached the 10k recommended limit and still had over 30% oil life remaining. I chanced the extended oil life and am now at 20% and 2000 miles past the 10k change interval. I'll change the oil before my next long journey. I wouldn't have trusted any other oil to run me past the recommended limit, but Amsoil has always met and exceeded my expectations. I'm an Amsoil customer for life.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Engine oil
    By  CHARLES,  a  Verified Buyer  from  Liberty Missouri   on  September 17, 2026

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    I can tell how the turbo works more freely with Amzoils diesel oil
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    6.7 Powerstroke
    By  ROBERT,  a  Verified Buyer  from  St. Augustine, Florida  on  September 17, 2026

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    This is peace of mind in a jug. I use this every oil change in my 2016 F350. Based on all my research and lab results, from several sources whom have tested this product against other brands. I know it's a little bit more than using some of the other available brands. However you get the added peace of mind knowing you're using the best product available for your truck. It's worth the added expense for me because I plan on keeping this truck until the wheels fall off.....
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Long time customer.
    By  JEROD,  a  Verified Buyer  from  NM  on  September 16, 2026

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    Love Amsoil products. The recent price increase of 20% is excessive in my opinion.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    AMSOIL DIESEL OIL
    By  JANEEN,  a  Verified Buyer  from  OR  on  September 07, 2026

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    AMSOIL produces superior Diesel oil products. I have used AMSOIL products for both gas and diesel Ford trucks for over 25 years. My 2011 F250, with 74,000 original miles, has all of its fluids changed with AMSOIL Diesel, Transmission, and Antifreeze products since the first 5,000 miles on the vehicle. My diesel mechanics swear this vehicle runs as well as it did when it was new at the dealership.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Diesel oil
    By  ALBERTO,  a  Verified Buyer  from  TX  on  September 05, 2026

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    quality
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    L5P
    By  JORDAN,  a  Verified Buyer  on  September 05, 2026

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    My truck love this oil.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Oil 15-40
    By  Jim,  a  Verified Buyer  from  Murrieta Ca  on  August 31, 2026

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    Great oil for my 05 Silverad with 278k miles, looking to the most out of her as best i can, that is why I use Amsoil products.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Only oil I use
    By  KEVIN,  a  Verified Buyer  from  Oregon   on  August 25, 2026

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    Best oil on the market for my 6.7 ford
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 4 star rating
    Year
    By  PAUL,  a  Verified Buyer  from  Eastern Washington   on  August 23, 2026

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    It bit more money. I BEEN use 10 30 in 6.7 ram foe year now with amsoil by only stay cleaner longer
    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

  
  
  
• Product Reviews
  4.9 star rating

  Based on 1,585 reviews

  Based on 1,585 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    Extended Oil Life
    By  Jerry,  a  Verified Buyer  from  NE  on  September 17, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I have a 21' Ram 2500 Mega Cab W/6.7 Ltr motor. I've used this oil since it's first oil change. 10,000 mile oil changes are recommended and I usually follow that recommendation consistently. This last change, I've monitored the trucks 'oil life' percentage gauge as I'm in the middle of a move and the truck is towing a 24'x8.5' enclosed trailer full of household stuff. I reached the 10k recommended limit and still had over 30% oil life remaining. I chanced the extended oil life and am now at 20% and 2000 miles past the 10k change interval. I'll change the oil before my next long journey. I wouldn't have trusted any other oil to run me past the recommended limit, but Amsoil has always met and exceeded my expectations. I'm an Amsoil customer for life.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Engine oil
    By  CHARLES,  a  Verified Buyer  from  Liberty Missouri   on  September 17, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I can tell how the turbo works more freely with Amzoils diesel oil
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    6.7 Powerstroke
    By  ROBERT,  a  Verified Buyer  from  St. Augustine, Florida  on  September 17, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    This is peace of mind in a jug. I use this every oil change in my 2016 F350. Based on all my research and lab results, from several sources whom have tested this product against other brands. I know it's a little bit more than using some of the other available brands. However you get the added peace of mind knowing you're using the best product available for your truck. It's worth the added expense for me because I plan on keeping this truck until the wheels fall off.....
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Long time customer.
    By  JEROD,  a  Verified Buyer  from  NM  on  September 16, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Love Amsoil products. The recent price increase of 20% is excessive in my opinion.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    AMSOIL DIESEL OIL
    By  JANEEN,  a  Verified Buyer  from  OR  on  September 07, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    AMSOIL produces superior Diesel oil products. I have used AMSOIL products for both gas and diesel Ford trucks for over 25 years. My 2011 F250, with 74,000 original miles, has all of its fluids changed with AMSOIL Diesel, Transmission, and Antifreeze products since the first 5,000 miles on the vehicle. My diesel mechanics swear this vehicle runs as well as it did when it was new at the dealership.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Diesel oil
    By  ALBERTO,  a  Verified Buyer  from  TX  on  September 05, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    quality
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    L5P
    By  JORDAN,  a  Verified Buyer  on  September 05, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    My truck love this oil.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Oil 15-40
    By  Jim,  a  Verified Buyer  from  Murrieta Ca  on  August 31, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Great oil for my 05 Silverad with 278k miles, looking to the most out of her as best i can, that is why I use Amsoil products.
    Bottom Line

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

    YES (0) NO (0)
  • 5 star rating
    Only oil I use
    By  KEVIN,  a  Verified Buyer  from  Oregon   on  August 25, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Best oil on the market for my 6.7 ford
    Bottom Line

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

    YES (0) NO (0)
  • 4 star rating
    Year
    By  PAUL,  a  Verified Buyer  from  Eastern Washington   on  August 23, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    It bit more money. I BEEN use 10 30 in 6.7 ram foe year now with amsoil by only stay cleaner longer
    Bottom Line

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

    YES (0) NO (0)