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

Product code : DEOQT-EA

4.9 star rating Read 1,206 reviews

Customer Rating

4.9

91% would recommend

  • 5 1151
  • 4 41
  • 3 5
  • 2 3
  • 1 6

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

4.9 star rating Based on 1,206 reviews
  • 5 star rating
    Diesel oil
    By  THOMAS,  a  Verified Buyer  on  July 04, 2024
    Great oil. Holds up well. Seems to keep everything running smooth. 160,000mi and no issues so far
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil !
    By  KYLE,  a  Verified Buyer  from  Barrie  on  July 02, 2024
    Great oil even under extreme heat my oil pressure is still good 👍🏼
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Tuff
    By  STAN,  a  Verified Buyer  from  Florida  on  July 02, 2024
    Amazing, bought this for my military house generator and i am glad I did! Great oil and products!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    My Cummings diesel is very important to me
    By  RANDY,  a  Verified Buyer  from  Catonsville, MD  on  June 29, 2024
    I have been driving my Cummings powered Dodge since 2013 and protect my engine with the best synthetic oil I can. AMSOIL is my choice.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel oil
    By  DAVID,  a  Verified Buyer  from  Saluda, South Carolina   on  June 27, 2024
    I use this oil in my 86 Chevrolet G30 Highcube van with a 6.2 non-turbo engine and the oil pressure increased about 5 psi and oil consumption on long trips decreased. Also the oil drips have decreased, cutting down on floor clean up.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 3 star rating
    Diesel oil
    By  Larry,  a  Verified Buyer  from  MT  on  June 25, 2024
    I can not give a review on any oil with very few miles on the vehicle I'm using it in. Get back to me in about !00,000 miles or about 6 or 7 years.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Awesome oil
    By  TANNER,  a  Verified Buyer  on  June 24, 2024
    High quality oil at an affordable price, definitely recommend to my friends and family. Preferred customer program is awesome too!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel oil
    By  CHRISTOPHER,  a  Verified Buyer  from  Oregon   on  June 23, 2024
    This oil works great and I like getting it delivered
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Longevity
    By  RON,  a  Verified Buyer  from  SoCal  on  June 23, 2024
    The oil more than meets expectations and being rated for 25k miles or 1 year is amazing on its own! Being that I drive this vehicle less than 6,000 miles a year, I guess I will be doing the annual oil change! So far, the motor seems to idle and run smoother and not stay in the high pressure state as long! I will definitely buy this again!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Awesomeness
    By  RICK,  a  Verified Buyer  from  Belle River  on  June 20, 2024
    I’m an 100% AMSOIL user I would not use anything but from my lawnmower to all vehicles and farm equipment
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    AMSOIL Signature Series 100% Synthetic Max-Duty Diesel oil
    By  JR,  a  Verified Buyer  on  June 20, 2024
    We have swapped to AMSOIL AMSOIL Signature Series 15W-40 100% Synthetic Max-Duty Diesel Oil which appears to be the best product on the market. The purchasing process and speed of delivery make AMSOIL a must buy product we will trust AMSOIL products in all of our equipment and vehicles.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Simply the best
    By  STEPHEN R,  a  Verified Buyer  from  Dallas  on  June 19, 2024
    I think this honestly may be the best oil ever for Cummins OTR trucks.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel oil
    By  ROBERT,  a  Verified Buyer  on  June 13, 2024
    Good oil
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Doing good
    By  DAVID,  a  Verified Buyer  from  Virginia   on  June 12, 2024
    Only have approximately 4K miles on the oil. Appears to still be consistent. Added a bypass system at same time. Waiting to reach 15K miles and send in sample for testing. Will follow up
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Oily stuff
    By  WILLIAM,  a  Verified Buyer  from  Southeast Indiana  on  June 11, 2024
    Bought this for my tractor after reading reviews and comparisons. My equipment is expensive, so I want the best in it. I'm told this is it. So far , so good.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Good stuff
    By  JOHN,  a  Verified Buyer  from  SoCal  on  June 11, 2024
    I use the 15-40 signature series in my RV with a 12.8 liter Mercedes Diesel. I noticed a difference on my way home from having the first oil change with the Amsoil. On our first trip my wife ask what I had changed. She said "the engine is quieter and smoother". Now it's the only oil I'll use. Thank you for a great product.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    First switch to the 25k mile oil.
    By  ERNIE,  a  Verified Buyer  from  Richmond va  on  June 09, 2024
    Oil should work great but was disappointed they did not have my oil filter in stock. I really want to shop for everything at one spot.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Simply the best oil
    By  MICHAEL,  a  Verified Buyer  from  Quebec Canada  on  June 08, 2024
    I reduce the consomption of oil of my truck in half !
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    2017 powerstroke
    By  SCOTT,  a  Verified Buyer  on  June 07, 2024
    Since using this oil the engine sounds and runs smoother and stays cleaner longer and I get better fuel economy. I trust no other brand. I use amsoil in anything that takes oil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Ford 6.0
    By  BEAU,  a  Verified Buyer  on  June 06, 2024
    Used it in two different trucks. And so far impressed with how smooth it sounds running. It seems to be quieter. I have 3k miles on one truck and 500 miles on another. Both trucks are ford 6.0’s. And so far I'm impressed.
    Bottom Line
    Yes, I would recommend this to a friend.
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