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AMSOIL Signature Series 15W-40 100% Synthetic Max-Duty Diesel Oil

Product code : DMEQT-EA

4.9 star rating Read 1,284 reviews

Customer Rating

4.9

92% would recommend

  • 5 1229
  • 4 41
  • 3 5
  • 2 3
  • 1 6

AMSOIL Signature Series 15W-40 100% Synthetic Max-Duty Diesel Oil

4.9 star rating Based on 1,284 reviews
  • 5 star rating
    Don’t go cheap on your diesel oil?
    By  GREGORY,  a  Verified Buyer  from  Washington State   on  February 01, 2025
    Put the best stuff you can afford in your diesel. Amsoil checks all the boxes for me and helps keep my diesel running like new. I change my oil every 5000k miles. For the cost it’s cheap insurance for my motor.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Fast shipping, and great a product
    By  ANDREW,  a  Verified Buyer  on  February 01, 2025
    Could not recommend more
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Would recomment
    By  BLAIR,  a  Verified Buyer  from  Alberta  on  January 27, 2025
    One my 3rd oil change on my new duramax now. I don’t do the recommended 25000km I change at 10000km I idle a lot more then most so it gives me peace of mind
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Fine product
    By  PG,  a  Verified Buyer  from  San Antonio  on  January 26, 2025
    Purchased my Ram 2500 truck in 2015 and since then, I've used AMSOIL Signature exclusively since 2018. The truck gets decent mileage whether driving "normally" or towing my travel trailers. I've not experienced any engine related issues at all, knock on wood.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Oil Change
    By  WAYNE,  a  Verified Buyer  from  Snyder Oklahoma  on  January 24, 2025
    I've been a devote user of Amsoil for my oil changes and it has always kept me going.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Pickup truck oil
    By  JEFF,  a  Verified Buyer  from  West Central Illinois  on  January 21, 2025
    I think the AMSOIL is the best oil on the market. The shipping is very fast. I usually receive the product the next day.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil
    By  MACK,  a  Verified Buyer  from  KS  on  January 21, 2025
    I have been using Amsoil for years now. The oil life and ease of getting it is great! I had my order delivered the next day after I ordered it.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel motor oil
    By  NATE,  a  Verified Buyer  from  Eden  on  January 19, 2025
    My 2004 Cummins runs flawlessly with this motor oil
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Amsoil Diesel Oil
    By  BRENT,  a  Verified Buyer  from  KC  on  January 18, 2025
    Best oil made, PERIOD. I’ve used it my whole life and it never lets me down. A++
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Quiet down a 6.7l ford
    By  BMAC,  a  Verified Buyer  from  Drayton Valley  on  January 17, 2025
    I have used the heavy duty oil from amsoil, which is great protection. Motor was still little noisy, and switched oil to this signature series and made the motor quiet down alot and run smooth. It's a good one to run.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great Oil
    By  MICHAEL,  a  Verified Buyer  from  Lancaster, SC  on  January 16, 2025
    I use to use Rotella T5 10W30 and was getting decent mileage and protection. When Shell couldn't get the additives to make the T5 oil I changed to Amsoil 10W30. Best decision I could have made! The oil gets me about .5 to 1 mpg increase. I love this oil! I'm glad I switched and don't plan on ever going back!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great stuff!
    By  CHARLIE,  a  Verified Buyer  on  January 14, 2025
    Love this oil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Newer Diesels
    By  CURTIS,  a  Verified Buyer  on  January 09, 2025
    I just bought a newer diesel 5th wheel hauler to replace our aged 2002 Duramax. The old truck only used Amsoil 15w-40 Marine Diesel Oil. The new truck takes 5w-40 full synthetic or 10w-30. Since the marine grade doesn’t come in 5w-40, I used the signature series. Looking forward to many years with this new truck using Amsoil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    AMSOIL Signature 5W-40 Synthetic Max-Duty Diesel Oil
    By  JOHN,  a  Verified Buyer  from  KS  on  January 08, 2025
    I began using the Signature 5W-40 Synthetic Max-Duty Diesel Oil in my 2024 New Ford F-350 with the new HO Diesel engine this past fall. I manage a large farm in Central KS and work in very extreme conditions. I’ve been more than happy with it’s performance and trust AMSOIL superior products will protect my engine for a long, long time.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Premium oil
    By  JEFF,  a  Verified Buyer  from  AZ  on  January 06, 2025
    Arrived quick. Great customer service.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    EXCELLENT OIL
    By  HEATH,  a  Verified Buyer  from  Colorado  on  January 04, 2025
    Can't get any better than Amsoil!!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Amsoil quality
    By  AARON,  a  Verified Buyer  on  January 03, 2025
    I have been using AMSOIL for years now and absolutely love it! I use the full synthetic and won't ever switch.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Works great
    By  JEFF C,  a  Verified Buyer  from  Lexington Kentucky   on  January 03, 2025
    Perfect thank you
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Perfect Lube for Cold Midwest Winters
    By  Jim,  a  Verified Buyer  from  Indiana  on  January 03, 2025
    I've been using AMSOIL 5W40 Diesel Oil in my John Deere 1025r for more than 10 years. I store the tractor outside under cover without benefit of a block heater. Even on the coldest, below zero mornings, the tractor starts right up with just one cycle of the glow plugs. Year round protection in all temperature extremes is why I've been an AMSOIL fan for more than 25 years.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Liquid gold
    By  JOHN,  a  Verified Buyer  from  Florida  on  December 31, 2024
    All Amsoil products are great but especially the quality of their signature line. I own a Ram 3500 (non dually) with the Cummins 6.7L and my engine runs whisper quiet with it. I can always tell quality oil with how long the engine takes to warm up. Not only that but the viscosity lasts longer than other oils. I'm something of a nerd to checking how thin the oil is when it drains and I always feel like I've changed my oil too soon. A great product hands down.
    Bottom Line
    Yes, I would recommend this to a friend.
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