Customer Ratings & Reviews

Great product. I’ve had it 3rd party tested and have put 40,000 miles on an oil change. Other than changing the filter to get a sample and adding the one quart back to it. You can go way further than the 25,000

Always a great product for my diesel engine along with Amsoil filter. Always quick shipping.

Great oil for diesels

I put the oil in my 2007 Duramax truck and my cadillac .Had timing chain replaced ,and the engine was clean when the timing cover was opened up .I was impressed on how clean my engine was.I have been useing this oil on both cars for 10 years now.Very happy.

great oil always makes my truck run so much better after oil change never an issues and knowing it can last up to 60,000 miles or one year gives me piece of mind . I always change after 20,000 just to be on the safe side but the oil always looks to be in good shape every time

Works as it should installed Banks Pan on engine and used Amsoil as recommended.

The kit comes with all the necessary items to do this job, gloves, funnel, oil, and filter. I received the kit in a timely manner. Thank you!

Very good oil

Best diesel oil on the planet!

I expected AMSOIL Signature Series 15W-40 100% Synthetic Max-Duty Diesel Oil to do well in my vehicle but I did not expect how much better than my usual Rotella T6 15W-40 it would do. I noticed right away fewer exhaust filter regeneration cycles that continue to get better to where I am almost at none and just maintaining a consistent level between 52% and 68%. I believe it took a while to fully get all the remaining Rotella oil out of the engine. After the second oil change using the Amsoil product it when I have been able to maintain exhaust filter percentage between the 52% and 68%. Fuel mileage has improved around 8-13%, along with a noticeable reduction in engine noise and improved power. Super pleased and will from now on only use the AMSOIL Signature Series 15W-40 100% Synthetic Max-Duty Diesel Oil in my 2021 GMC 3500HD Duramax.

So far working as claimed and truck seems to be more quite compared to using Rotella T6 5W-40 (winter) & Rotella T6 15W-40 (summer)

Very fast shipping and in perfect condition

Best diesel oil and automotive oil on the planet!

Great oil, great website, and fast shipping. Can't beat it.

I've been using Amsoil for a while. Their quality is really good and I'll keep using it.

I researched several brands of Full Synthetic Diesel Oil for use in my 2016 F350 with the 6.7 Powerstroke. The Signature Series was my choice because of all the results I read and reviews I watched. Its the best in my opinion for my driving style and the extra weight of my truck plus the over sized tires. I follow the severe duty maintenance schedule.

Runs better than shell rotella

This is the only motor oil I run in my 2007 6.0 Powerstroke; it runs amazing on it. Injectors fire beautifully, as they're run off high pressure oil in this motor. I know that I am putting the best quality oil in my truck when I use this product. I know many other people with the same generation of truck as mine, they're all running AMSOIL as well. Highly recommend.

I have used Amsoil for years and continue with my newer Cummins with roller lifters, 30,000 miles and no issues.

Highly recommend all of their diesel products! My Titan loves when these fluids are in her!!!