Customer Ratings & Reviews

With the oil bypass system on my GMC 3500HD, I Change the oil and both filters at 15k miles. The system takes about 14qtrs, and this size jug saves time not having to open 10 individual qtrs.

I have a John Deere 2305 Tractor that I've always just changed the oil using the John Deere brand oil. I believe in the AMS Oil brand as an industry leader and wanted to try AMSOIL Signature Series 5W-30 Synthetic Max-Duty Diesel Oil. I noticed a difference on easier starts and quieter operation at all RPMs. The throttle response improved too. That was my experience.

Been using Amsoil since 2007

The Cummings ISV 5.0 engine is prone to engine problems. I’ve been using this oil and the oil samples I send out always come back with great ratings. They tell me very low ware and all the readings are well below range. I highly recommend this oil.

Expensive oil but good . I run it in my 12 valve Cummins in the wi winters

I have been changing oil on multiple vehicles for over 50 years. After much research I decided to switch to Amsoil starting with my 2025 2500 GMC AT4X Duramax. My first purchase was on line from Amsoil and my second purchase was from a local distributor. Both experiences were flawless and with the online purchase I never left my house and the delivery was quick and on time. I will continue to purchase online as the entire delivery process was as promised. The packaging was as expected. No complaints.

I have been using this product since my GMC w/ diramax was new in 2012. I change the filter and top off at 7500 miles and change oil and filter at 15000. The truck now has 275k without any lubrication issues.

Great product! No more ticking sound!

To use this oil in conjunction with the EA098 filter and change every 15,000 miles. I feel confident this will help protect my 6.7L diesel engine better than any other products.

Running this oil for a while. Ran to 10,000 miles and sent sample in and they said to go another 5,000. I’m satisfied. Also run Amsoil in the Harleys. Definitely worth the money.

I attribute my 265,000 plus miles on my 2002 chev. 2500 HD 6.6 to AMSOIL I use the 1540 synthetic and the AMSOIL oil filter I get 8000 plus miles between oil changes saves me money

Best oil and product been using since I purchase my truck

Amsoil is the best oil I have ever used in my diesel truck. I love the protection it gives my engine. Runs great

Been running Amsoil 15-40W fully synthetic since 70000 miles. Almost 300000 25 years old in January. Motor still runs like a scalded dog. No oil related problems. Change oil once a year. Only had to replace injectors and glow plugs around 265000. Not really any engine problems due to oil.

First time user, not sure but heard this oil is the best

Just changed the oil for the first time in the new truck. Ran ams oil in all my small engines and hasn’t disappointed. Plus free stickers in every box is a huge bonous for us oil and gas workers

Good delivery service

I bought a 2008 Ram 2500 6.7L recently. This is my first diesel. Everyone that I have spoken to talks about the quality of Amsoil's products. I decided to become a preferred customer and switch the truck over to Amsoil. I hope this decision gives me hundreds of thousands of miles of life in this truck.

This is all I will ever run it’s worth the money I’m a preferred customer and everyone that I have turned onto Amsoil after an engine flesh has said their vehicle has never ran better smoother and they could feel the power increase. I would love to become a dealer one day and convert every oil in my truck to amsoil best product I have ever used

I love this oil. When it's cold out the engine spins over just like it does it the summer.