Excellent product for its wear protection. Zero oil consumption. No worries when you occasionaly go past recommended oil change intervals. Oil temperatures stay lower under higher loads. 2.5 gallon container size is an added plus.

Use to use other motor oil on my Duramax and it would burn roughly a quart every 4k miles. Truck does not burn this stuff and oil still looks brand new after 3k miles. Highly impressed by it and recommend it.

very good quilty oil will be buying again

In my 2004 dodge diesel, which was purchased new, I have used Amsoil oil and filters since it's first oil change, about 490,000 miles ago, with no engine repairs required. I change the oil and filter once a year or about 25,000 miles. Highly recommend. I use Amsoil products in everything that needs oil, Tahoe, 4-wheeler, lawnmower, outboard motor, etc.

My Amsoil dealer ALWAYS gets my products to me way faster than expected!! The brand speaks for itself, so having the added excellent service keeps me coming back everytime!!!

Put the best stuff you can afford in your diesel. Amsoil checks all the boxes for me and helps keep my diesel running like new. I change my oil every 5000k miles. For the cost it’s cheap insurance for my motor.

Could not recommend more

One my 3rd oil change on my new duramax now. I don’t do the recommended 25000km I change at 10000km I idle a lot more then most so it gives me peace of mind

Purchased my Ram 2500 truck in 2015 and since then, I've used AMSOIL Signature exclusively since 2018. The truck gets decent mileage whether driving "normally" or towing my travel trailers. I've not experienced any engine related issues at all, knock on wood.

I've been a devote user of Amsoil for my oil changes and it has always kept me going.

I think the AMSOIL is the best oil on the market. The shipping is very fast. I usually receive the product the next day.

I have been using Amsoil for years now. The oil life and ease of getting it is great! I had my order delivered the next day after I ordered it.

My 2004 Cummins runs flawlessly with this motor oil

Been using for many years with great results. I have been changing my oil once a year with no Issues.

Best oil made, PERIOD. I’ve used it my whole life and it never lets me down. A++

I have used the heavy duty oil from amsoil, which is great protection. Motor was still little noisy, and switched oil to this signature series and made the motor quiet down alot and run smooth. It's a good one to run.

I use to use Rotella T5 10W30 and was getting decent mileage and protection. When Shell couldn't get the additives to make the T5 oil I changed to Amsoil 10W30. Best decision I could have made! The oil gets me about .5 to 1 mpg increase. I love this oil! I'm glad I switched and don't plan on ever going back!

Love this oil.

I just bought a newer diesel 5th wheel hauler to replace our aged 2002 Duramax. The old truck only used Amsoil 15w-40 Marine Diesel Oil. The new truck takes 5w-40 full synthetic or 10w-30. Since the marine grade doesn’t come in 5w-40, I used the signature series. Looking forward to many years with this new truck using Amsoil.

I began using the Signature 5W-40 Synthetic Max-Duty Diesel Oil in my 2024 New Ford F-350 with the new HO Diesel engine this past fall. I manage a large farm in Central KS and work in very extreme conditions. I’ve been more than happy with it’s performance and trust AMSOIL superior products will protect my engine for a long, long time.