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

Product code : DEOQT-EA

4.9 star rating Read 1,153 reviews

Customer Rating

4.9

91% would recommend

  • 5 1100
  • 4 40
  • 3 4
  • 2 3
  • 1 6

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

4.9 star rating Based on 1,153 reviews
  • 5 star rating
    Using this oil for many years
    By  MAHRAD,  a  Verified Buyer  from  Central Florida  on  August 27, 2023
    I have been using the 15 W 40 Amsoil diesel oil for many years on different GMC Duramax diesels. All on lower mileage trucks. It is a good durable oil. No burning of loss of oil. No engine mechanical issues. I perform the oil changes myself. Libricity of the old oil is very good. The 2.5 gallon container is difficult to handle without spilling. I recommend getting it in quart size containers. I recommend the oil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Fast Delivery
    By  CRISANTO,  a  Verified Buyer  from  Sammamish Wa  on  August 26, 2023
    Great oil at a good price. Overnight delivery
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Amazing
    By  JOHN PAUL,  a  Verified Buyer  on  August 24, 2023
    This product is spectacular, immediately noticed improved performance in my truck and I would not use any other brand besides amsoil for diesel engines!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 4 star rating
    The trip
    By  KK,  a  Verified Buyer  from  Plymouth wi to masa AZ   on  August 20, 2023
    I use 5W-40in my 3VW TDI WHEN I TOOK a trip to AZ 122 temp I seen my oil in my Commons diesel pick up to literally evaporate the oil. In Wisconsin, my truck doesn't use any oil. In outer Arizona, it evaporates the oil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Amsoil 5-40 oil for diesels
    By  Robert,  a  Verified Buyer  from  FL  on  August 19, 2023
    This is the only oil that I have found that does not cause me problems with my diesel exhaust filter. No regens since I have been running it. Ram 1500 ecodiesel.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    I’ve been feeding my 5.9 24Valve since 2017
    By  ROBERT SCOTT,  a  Verified Buyer  on  August 18, 2023
    I’ve been using AMSOIL in my Ram 2500 motor and transmission since I had to replace my Transmission. My Transmission has never had anything other than AMSOIL in it. At the same time as the new transmission I did a AMSOIL engine flush and after a little over 100 miles drained it and added the AMSOIL and AMSOIL filter and it’s worked great. I change my oil every 15,000 mile with fresh AMSOIL and a filter with no issues. I also changed out my coolant and my truck highway miles is down in temp. No complaints from me.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    The REAL Deal!!!
    By  JOHN,  a  Verified Buyer  from  Texas   on  August 08, 2023
    We used to run Amsoil in oil fleet vehicles years ago, don’t know why they got away from it. Anyways, I run a 2019 Chevy DRW, bought it with 92k. First oil change I did, went with Amsoil Signature. Went to oil change interval recommended by GM (approx 7k miles). I tow a 14-16k 5th wheel light/ moderate distances several times a year. Had the oil tested by a 3rd party, analysis came back I could go to 10k. Levels tested still well above normal for oil with the mileage and oil filter was still good. Don’t know how they could test that, but they did. Went 10k miles on next interval, had it tested again, same tests, same company. Analysis came back less than before, but still above acceptable levels according to them. Have a sample from 15k miles waiting to be tested. I can say, all of my vehicles now use Amsoil signature!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Max Duty Synthetic Oil 15W-40
    By  ALVARO,  a  Verified Buyer  on  August 07, 2023
    Ordered product and came very fast! Very satisfied with company. Thank you. A
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    80 kw ohan cummins generator
    By  GARY,  a  Verified Buyer  from  dauphin island  on  August 06, 2023
    run this in my generator for a peace of mind knowing it's the best
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  • 5 star rating
    Best oil
    By  JOSE,  a  Verified Buyer  from  Round Rock Tx  on  August 05, 2023
    Best oil
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Has stood the test of time
    By  JERRY,  a  Verified Buyer  on  August 03, 2023
    I have been using this in my truck for 27 years and my truck still runs great. 352,000 miles.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Outstanding
    By  KEVYN,  a  Verified Buyer  from  Texas   on  August 02, 2023
    This exact oil saved a motor that blew a head gasket and lost all but 2 of the 14 quarts. Ford mechanic was amazed at how good the cylinders still looked. He stated he had many that had the same problems but all the others the motor was trash. Mine just had to have a new head gasket engine flush fresh oil and antifreeze. Then was back on the road.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Best stuff out there
    By  DAVID,  a  Verified Buyer  from  Florida   on  August 02, 2023
    This oil is the only oil I’ll use on my diesel truck!! She’s 11 yes old and runs like a champ
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Quality
    By  ANDREW,  a  Verified Buyer  from  Mo.  on  August 01, 2023
    I use this oil in my M35A2 multi fuel deuce and half stays clean longer engine runs better this is a high quality product
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great package
    By  TJ,  a  Verified Buyer  from  Folsom, CA  on  August 01, 2023
    Great product, great package.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    top products
    By  HERLAN,  a  Verified Buyer  on  July 31, 2023
    use Amsoil products on all my equipments
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Diesel Oil
    By  STEPHEN,  a  Verified Buyer  from  Salida, CO  on  July 30, 2023
    Have used this oil since OEM break-in oil on my 2018 RAM 3500 w/ Cummins HO 6.7. At 3000 mi switched to Everything AMSOIL! I get yearly oil analysis reports on this oil and it comes back fantastic every time. It’s well worth using diesel oil and AMSOIL filters too.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Does the job well
    By  NATHAN,  a  Verified Buyer  on  July 29, 2023
    Switched from royal purple to this because the LB7 would not hold oil pressure when it was hot and it was burning oil and it never did before using the purple. Truck now holds oil press at 30 at idle when hot and is back to not using oil. Will not use anything else in this truck now
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Only the best!
    By  ANDREW,  a  Verified Buyer  from  Lebanon, IN  on  July 27, 2023
    This product has the best anti-wear properties offered by any manufacturer. The 2.5gal jug is exactly what my vehicle requires. Customer support is amazing. The wide range of products offered by Amsoil makes them a one stop shop for any internal combustion engine you may have. I highly recommend Amsoil for your next and future needs!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Really great product.
    By  DALLAS,  a  Verified Buyer  from  Phoenix AZ  on  July 18, 2023
    I have a 2019 and 2023 Duramax and I always use Amsoil it both. The oil pressure and temp stay very consistent doesn’t matter if it is fresh or at 8,000 miles.
    Bottom Line
    Yes, I would recommend this to a friend.
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