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

Product code : DMEQTC-EA

4.9 star rating Read 1,537 reviews

Customer Rating

4.9

92% would recommend

  • 5 1472
  • 4 45
  • 3 9
  • 2 3
  • 1 8

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

4.9 star rating Based on 1,537 reviews
  • 5 star rating
    ss diesel oil 5w-40
    By  EDDIE,  a  Verified Buyer  from  Georgia  on  January 31, 2023
    I have been using Amsoil Oil products in all of my vehicles since 2008. 07 3500 6.6 Durmax, 97 surburban, 06 HD, 02 Tahoe sold 400k Plus miles, 24yr old Dixie Chopper twin Kohler engine 72 " still running, power small engines eqpt, Purchased a new 20 surbura legacy , skip the free Dealership oil service, Back Hoe the pound out grease is amazing. I use 89 octane in all gasoline engines , my maint. has been kept to a min. Thanks AMSOIL ! great products !
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great Product
    By  CHARLIE,  a  Verified Buyer  from  TX  on  January 27, 2023
    Great product especially in colder weather on engine start-ups. Engine doesn't clatter as it has before when using a higher viscosity oil. If all the Amsoil testing is validated then I know I am getting the best possible protection for my trucks. My '04.5 Cummins HO truck that I bought new has never had an issue with the engine. Still going strong. Very important to not only have the best oil for your engine but for the life of that turbo as well.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    🇺🇸🇺🇸🇺🇸
    By  JASON,  a  Verified Buyer  on  January 21, 2023
    Great products and 💯🇺🇸 made. Customer for life!!! I love the guaranteed protection on the parts the oils come in contact with. Switched from R**** P***** after using them for 13 years and can tell my motor is running smoother.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    I am amazed.
    By  jason,  a  Verified Buyer  from  NJ  on  January 21, 2023
    I used this for my newly rebuilt 1990 Jeep YJ 4.7 stroker. 4.2 Jeep motors were known for noisey lifters after the engine is up to temp. This oil has dramatically quieted my motor down. My oil pressure is 7psi higher at idle and 12 psi higher under load. This is compared to Rotella T6 15w-40. My cold start lifter tap is HALF the time (in seconds) that Rotella was. Let's say Rotella was 2-3 seconds of noise. Amsoil Diesel 5w-40 is 1.5 seconds of tap in the morning on a cold start. I was a faithful Rotella user for years. Well now I am loyal to Amsoil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    oil upgrade
    By  ALLAN,  a  Verified Buyer  from  OK  on  January 18, 2023
    wanted up upgrade to the 5W-40 for the winter starting performance over my previous 15W-40. The oil pressure does come up a little faster.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    oil upgrade
    By  20Tremor,  a  Verified Buyer  from  21771  on  January 18, 2023
    made the switch to Amsoil based on previous experience using 10W-30 in a 86 Bronco II and a 88 straight 6 F250. Also, reviews from a couple of diesel forums gave good reviews. i have made 3 oil changes to my 6.7L and the oil coming out doesn't seem to be as gritty as the syn. penz. i was using.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great Product
    By  MIKE,  a  Verified Buyer  from  Lancaster, SC.  on  January 14, 2023
    I decided to use this oil in my 2015 F-350. It seems to be doing much better than the old oil I was using. I will be using this oil from now on.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Good oil
    By  THOMAS,  a  Verified Buyer  from  Kamloops B.C.  on  January 14, 2023
    Good oil for a reasonable price super quick shipping. Great staff to deal with.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great for heavy duty protection
    By  FERNANDO,  a  Verified Buyer  from  Vancouver wa  on  January 08, 2023
    It gives peace of mind knowing that the engine is protected.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great Product
    By  QUINTON,  a  Verified Buyer  on  January 08, 2023
    Exceeds standard. Great product
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great product
    By  PIERRE,  a  Verified Buyer  from  Casselman Area  on  January 05, 2023
    Have been using Amsoil for over 38 years
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Cummins 6.7 Requirement
    By  WYATT,  a  Verified Buyer  from  SC  on  January 05, 2023
    It’s comforting knowing your using the best product available.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Fantastic product
    By  JORDAN,  a  Verified Buyer  on  December 29, 2022
    I run Amsoil in everything truck I own.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Excellent
    By  KEVYN,  a  Verified Buyer  from  Amarillo TX  on  December 28, 2022
    AMSOIL makes absolutely first class products. I have never had an issues with their products. This particular oil saved a motor in a truck of mine that blew a head gasket and dump all the oil but 11/2 quarts. The mechanic who redid the head gasket was astonished that the cylinders and cylinder walls look like a brand new block with 100% of the cross hatches still intact.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Data
    By  RAM,  a  Verified Buyer  from  Nashville   on  December 24, 2022
    I’m happy to afford the best oil for my Cummins motors. They work hard to make me money and deserve the best.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    15-40 oil
    By  MICHAEL,  a  Verified Buyer  from  Pa   on  December 19, 2022
    I have been using Amsoil for over 10 years now and totally pleased with the product. I have a 2001 F350 7.3 have 257,000 miles Plus the fact it is delivered toy your door within days.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great stuff
    By  JAMES,  a  Verified Buyer  on  December 18, 2022
    Great stuff, only change every 25000 miles
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil
    By  STEVE,  a  Verified Buyer  on  December 17, 2022
    Works well
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    SAE 5W-40
    By  CLINTON,  a  Verified Buyer  from  Berlin  on  December 12, 2022
    First time using Amsoil. I did a lot of research and follow an R&D company in California that produced video segments on your production process. I have noticed a difference in my Cummins engine running. It does seem smoother and idles better. This is going to be my new engine oil from now on.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Amsoil Full Synthetic
    By  JC,  a  Verified Buyer  from  Riverside, CA.  on  December 11, 2022
    Got turned on to Amsoil a few years ago and will have to say it is the best thing that has happened to my 05 F150 5.4 3 valve, the notorious engine loaded with issues. Since using it, oil consumption-gone, engine noise-almost non-existent.
    Bottom Line
    Yes, I would recommend this to a friend.
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