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Customer Ratings & Reviews

Customer Rating

4.9

92% would recommend

  • 5 1506
  • 4 46
  • 3 10
  • 2 3
  • 1 8

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

Product code : DEOQTC-EA

4.9 star rating Read 1,573 reviews
Current price:

$21.39

Retail Price (CAD)
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AMSOIL Signature Series 5W-40 100% Synthetic Max-Duty Diesel Oil

4.9 star rating Based on 1,573 reviews
  • 5 star rating
    Great product
    By  KEVIN,  a  Verified Buyer  from  South Carolina   on  October 10, 2025
    Can not say enough about this product and Amsoil. I am a little bias but swear by everything Amsoil. Always keeping my diesel properly lubricated all through the 10k oil changes.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Best oil
    By  LUIS,  a  Verified Buyer  from  Texas  on  October 09, 2025
    excellent product
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel oil
    By  RUSS,  a  Verified Buyer  from  Minnesota  on  October 07, 2025
    I will only use the signature series oil in my super duty. I’ve been using it for years now. Absolutely love it!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel oil kit
    By  RORY,  a  Verified Buyer  from  Nevada  on  October 07, 2025
    Excellent Service. Quick delivery on a great product
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil
    By  WAYNE,  a  Verified Buyer  from  Idaho  on  October 06, 2025
    It has improved my oil pressure an reduce my engine noise
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great
    By  GAVIN,  a  Verified Buyer  on  October 05, 2025
    As advertised
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Good stuff
    By  SCOTT,  a  Verified Buyer  on  October 04, 2025
    Good stuff. 180k on 6.7. No issues I like the 2.5 gallon jugs
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    DIESEL OIL
    By  RONALD,  a  Verified Buyer  from  PHIPPSBURG COLORADO  on  October 02, 2025
    I HAVE USED AMSOIL SINCE 1980, I HAVE USED THIS OIL SINCE 2008 IN THIS DIESEL. I WOULD NOT USE ANYTHING ELSE.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel Oil
    By  JAMES,  a  Verified Buyer  from  Texas  on  October 01, 2025
    Best oil on earth.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great Engine Protection
    By  DANIEL,  a  Verified Buyer  from  Alva Wyoming   on  September 26, 2025
    I’ve always been a “Royal Purple” guy, it’s a top of the line product as is their other products- BUT after running Amsoil 15W40 in my 2013 HD Silverado Duramax, it’s “Light Years”better for my MPG, engine oil temperature and power.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Best Diesel Oil
    By  Dick,  a  Verified Buyer  from  Casco Maine  on  September 21, 2025
    I've been using Amsoil diesel oil for 14 years and my engine runs great.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel oil
    By  JEFFREY,  a  Verified Buyer  on  September 21, 2025
    Great oil. Even put in my diesel tractor. Turbo spools a lot faster.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    EXCELLENT PRODUCTS!!
    By  TXGREEK ,  a  Verified Buyer  on  September 21, 2025
    Excellent products!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Best there is
    By  RAFAL,  a  Verified Buyer  from  Okinawa, Japan  on  September 19, 2025
    I was turned on to Amsoil for my lawncare equipment, then I switched to it for all of my products. I use Diesel Oil in my Hino Dutro, with a 4 liter diesel engine to tow my trailer, I drive relatively low miles, maybe 10K a year and only change my oil once a year and Amsoil is amazing for providing protection for my truck even on yearly basis.
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  • 5 star rating
    Great
    By  LANCIER,  a  Verified Buyer  on  September 17, 2025
    Great oil
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    What more can you say?
    By  JON,  a  Verified Buyer  on  September 14, 2025
    Tried and true, longer lifespan and great for engine health. What more can you say or ask for from a quality product that’s been proven for years.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Power
    By  KIPPER ,  a  Verified Buyer  from  Michigan  on  September 11, 2025
    My diesel is a beast in real hot weather, but in Michigan we just don’t get the heat so adding this definitely gives it boost along with some better mileage!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Oil
    By  JAMES,  a  Verified Buyer  on  September 11, 2025
    Best oil ever
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    winter oil
    By  DAN,  a  Verified Buyer  from  Weyburn Sk.  on  September 11, 2025
    Best oil i've used in my old 2011 dodgeram 2500 6.7 cummins and i can run for 30000km per changes with the 15w40 400000km on her and still running deluxe!!!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Seems to be working good
    By  JOHN,  a  Verified Buyer  from  Ohio  on  September 09, 2025
    First oil change with amsoil seems to have quieted most cummins clunks and ticks. Will see long term....
    Bottom Line
    Yes, I would recommend this to a friend.
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