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

Product code : DEOQTC-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 5W-40 100% Synthetic Max-Duty Diesel Oil

4.9 star rating Based on 1,537 reviews
  • 5 star rating
    signature-series-max-duty-synthetic
    By  RODNEY,  a  Verified Buyer  from  Texas  on  December 10, 2022
    I highly recommend Amsoil products to anyone who is interested in keeping their diesel or gas engine running far longer than any other oil. This is especially true for anyone who uses their diesel vehicles as hard as I do. I keep up with the maintenance but I haul trailers with loads of 10,000 to 14,000 lbs sometimes 1,000 to 1,200 miles at 75 to 80 miles an hour. I rely on Amsoil to keep my pickup going and I haven’t had a oil related failure with my current pickup or the last two that I owned. Can’t say about the oil I was using before.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great for the diesel
    By  SCOTT,  a  Verified Buyer  from  Michigan   on  December 04, 2022
    Extra protection for the truck. All lubricants have been changed to Aimsoil.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    I trust this stuff.
    By  AL,  a  Verified Buyer  on  December 04, 2022
    Lab testing says 'oil's still good' after 17K miles in a Duramax. Been using this since '06. Only oil I'll use in my LBZ!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil
    By  PHIL,  a  Verified Buyer  from  Lex Pk  on  December 02, 2022
    I have been using Amsoil in my Dodge 2500 5.9L for a long time and it is the only oil I trust. All of the Amsoil products provide the best performance and protection. They are the only ones I use.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Best oil you can buy.
    By  JOHN,  a  Verified Buyer  from  Long Island NY  on  November 28, 2022
    Anything Ams is too quality top notch beats everyone else. If you don't believe me get an couple old pans and an OUTDOOR camp stove. Put AMS against anything else and I garantee it will shock you. Be careful. I simply won't put anything else in my vehicles or toys.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Signature Series provides a noticeable difference
    By  AUSTIN,  a  Verified Buyer  on  November 27, 2022
    I have used other brands’ cheaper full synthetic engine oils in the past, but after switching to Signature Series oil in my ‘97 12v, I have noticed quieter and smoother engine operation from the oil change alone. My truck is going on 400k miles, and it’s safe to say it will the Signature Series treatment going forward.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Amsoil synthetic oil
    By  DWAYNE,  a  Verified Buyer  from  Terrace BC  on  November 25, 2022
    I broke my 2003 duramax in and switched to Amsoil 15-40 and now have over 800,000kms on it with out ever removing the valve covers and it is still running strong
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Signature series max duty
    By  SHANE,  a  Verified Buyer  on  November 22, 2022
    I have a lifted 2014 ram 2500. since I start using amsoil it runs smoother and quieter for longer. I 100% recommend them
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    2011 GMC SIERRA 3500HD Diesel oil change
    By  TONY,  a  Verified Buyer  from  Arizona  on  November 21, 2022
    Ordering from AMSOIL is always super fast shipping and the best quality of oil out there. I run it in all my Vehicles which is including my 18 turbo RZR and my built Harley.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Second Time Around!
    By  Mr. Lobo,  a  Verified Buyer  from  Elk River, MN  on  November 21, 2022
    What can possibly be better than Amsoil? If you could eat this product, I would have it for breakfast daily!
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 1 star rating
    Good oil
    By  ANDREW,  a  Verified Buyer  from  Washington   on  November 20, 2022
    Been good oil for me but it’s the 2nd time I’ve got the wrong filter that I ordered. I quit ordering for this reason because I live far out. Had to go buy a new filter again and now I this one that doesn’t fit.
    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  Pa  on  November 13, 2022
    Been running this oil from new purchase 2016 of truck
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil....
    By  Merrill,  a  Verified Buyer  from  Arizona  on  November 09, 2022
    Great oil for my 2017 F250 6.7 diesel.. gear boxes an tranny next.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Beat oil out there
    By  DAVID,  a  Verified Buyer  from  Florida  on  November 06, 2022
    This is the best oil out there! I won’t use anything but amsoil product in my truck and car
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Good quality oil
    By  DOUGLAS,  a  Verified Buyer  from  North Texas  on  November 01, 2022
    I like Amsoil's quality and their constant testing.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil
    By  PAUL,  a  Verified Buyer  on  October 31, 2022
    We go 8000 mi. Between oil change now
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great oil, and it was in stock
    By  CHRIS,  a  Verified Buyer  on  October 27, 2022
    Like the title says great oil, and it was in stock when I ordered it, and arrived with in a week of ordering. Planned on changing to Amsoil, and when the stores supply of the other brand I had used I changed.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Flip
    By  PHILLIP,  a  Verified Buyer  from  Pennsylvania   on  October 25, 2022
    I have your products in racing with great success. The diesel oil is for my wife’s truck which she makes trips to Tennessee, Missouri,Kentucky,& Texas pulling a43 ft horse trailer I like make sure things are protected the best way possible I believe Amsoil does that.
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Best oil on the market!
    By  BURT,  a  Verified Buyer  from  Lancaster, PA  on  October 22, 2022
    Best oil on the market! You can actually feel the difference when you put some between your finger tips. I trust this oil in my '96 Powerstroke for a year at a time. (I don't put a lot of miles on it in a year).
    Bottom Line
    Yes, I would recommend this to a friend.
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  • 5 star rating
    Easy pack problem
    By  EUGENE,  a  Verified Buyer  on  October 22, 2022
    The easy pack seal is very hard to open, and a pain in the but, the seal on top is not easy to open, first I tried to pull on the tab, could not open seal, then I got pliers, ripped the tab off trying to open, then I used my pocket knife, poked a hole in the seal, then used pliers to tear it off…..holy crap….that needs change, the oil I have no complaints about….excellent oil.
    Bottom Line
    Yes, I would recommend this to a friend.
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