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Customer Ratings & Reviews

Signature Series Max-Duty Synthetic Diesel Oil 15W-40

Product code : DMEQT-EA

4.9 Read 547 reviews

Customer Rating

4.9

84% would recommend

  • 5 518
  • 4 25
  • 3 1
  • 2 1
  • 1 2

Signature Series Max-Duty Synthetic Diesel Oil 15W-40

4.9 Based on 547 reviews
  • 5
    Nice for Duramax
    By  BOBBY,  a  Verified Buyer  on  May 01, 2021

    Describe the issue

    Actually added a couple of mpg on my 2003 Duramax. Like the product.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Perfect application
    By  LESTER,  a  Verified Buyer  from  Brighton TN  on  April 25, 2021

    Describe the issue

    Even the local Ford place recommends and will service my F250 with Amsoil
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Oil review
    By  STEVE,  a  Verified Buyer  from  Munford TN  on  April 24, 2021

    Describe the issue

    Best oil on the market love it
    Bottom Line
    Yes, I would recommend this to a friend.
  • 4
    Good product
    By  NEWTON,  a  Verified Buyer  from  Weatherford tx   on  April 24, 2021

    Describe the issue

    Good oil, have over 7000 miles and still clean for a diesel.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Best oil I've tried
    By  TERRY,  a  Verified Buyer  from  IA  on  April 23, 2021

    Describe the issue

    BETTER COLD STARTS AND WARM WEATHER PRESSURE THAN SYN ROTELLA I CAN'T THINK OF ONE THING I DONT LIKE ABOUT THIS OIL
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Best oil for your diesel.
    By  MILES,  a  Verified Buyer  on  April 22, 2021

    Describe the issue

    As always amsoil performs great. Cold starts are much easier, and the oil flows much more readily based on oil pressure readings. I’ve ran amsoil products in everything from motorcycles to diesel trucks and can’t recommend it enough.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great product
    By  BILLY,  a  Verified Buyer  on  April 19, 2021

    Describe the issue

    Absolutely the best oil I’ve ever used.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great product fast shipping
    By  ERIC,  a  Verified Buyer  from  Pennsylvania   on  April 19, 2021

    Describe the issue

    Love this product
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Amsoil Products
    By  LAURENCE,  a  Verified Buyer  on  April 18, 2021

    Describe the issue

    I have been using Amsoil products for 30 years. Need I say more???
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great Products
    By  DOUG,  a  Verified Buyer  from  Lethbridge   on  April 17, 2021

    Describe the issue

    I love being able to order direct from amsoil . It is extremely convenient and the quality of the products is second to none.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    The best oil that I can afford
    By  DAN,  a  Verified Buyer  from  Kentucky   on  April 15, 2021

    Describe the issue

    I use this oil in my freightliner Cascadia and in my 2017 powerstroke with an Amsoil bypass filter with regular oil analysis this oil has proven itself.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Cant beat the price!
    By  BOBBY,  a  Verified Buyer  from  TX  on  April 15, 2021

    Describe the issue

    I like to try and test oils in my vehicles. Ever since my oil analysis kept coming back positive from a 3rd party oil analyst company, I have stuck with AMS. It seriously is not snake oil. And my trucks love it. Idle quiter and sustained fuel economy improvement. Meaning that it stays constant with fuel economy. It doesn’t jump up or down, just level.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great diesel oil
    By  ALFREDO,  a  Verified Buyer  on  April 12, 2021

    Describe the issue

    Overall great oil
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    best stuff in the market
    By  RONNIE,  a  Verified Buyer  from  lake Anna   on  April 12, 2021

    Describe the issue

    best stuff on the market use it in my truck and both my Harleys
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Go to in Ford 6.7 powerstroke
    By  CHRIS,  a  Verified Buyer  from  new Hampshire  on  April 11, 2021

    Describe the issue

    When you ante up $10K for the industries most powerful diesel you want to take steps to ensure it is well kept. Have been using thee Signature Oil with the Amsoil by-pass system. Have been happy with the results. Highly recommended.
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Quiten that Diesel down!
    By  Billy,  a  Verified Buyer  from  Virginia  on  April 11, 2021

    Describe the issue

    So, it was time to change the oil in my John Deere 2025r. Being a Amsoil PC I decided to try Amsoil in my tractor. I used Amsoil Engine Flush before pulling the plug and after draining my oil I'm glad I did! My oil was full of soot and carbon! After installing my Amsoil filter ( got the filter recommendation from Amsoil Tech.) I added some fresh Amsoil 5w-40 and started my JD up. I've never heard it run so quite! Almost sounded like a gas engine it was so quite! Looking forward to seeing if I can ' feel the protection' when I use it !! Thanks Amsoil!
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Best oil by far
    By  OLIVER,  a  Verified Buyer  from  Canada  on  April 11, 2021

    Describe the issue

    I used this oil for years in my truck and my cars. Best oil by any circumstances
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Diesel oil
    By  ROBERT,  a  Verified Buyer  from  Brandon vermont  on  April 11, 2021

    Describe the issue

    I have been using this oil the truck has over 200 thousand miles and going strong I change it once a year and I also a change the filter at 6 months intervals
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Great oil
    By  FRED,  a  Verified Buyer  from  Arizona  on  April 10, 2021

    Describe the issue

    Love this oil for my Duramax diesel. Just made a 3,000 mile trip and didn’t have to add any. Love the wide mouth of the quart container as it pours really fast
    Bottom Line
    Yes, I would recommend this to a friend.
  • 5
    Diesel Oil
    By  JANEEN,  a  Verified Buyer  from  Oregon  on  April 09, 2021

    Describe the issue

    Superior product.
    Bottom Line
    Yes, I would recommend this to a friend.