I have used Amsoil 5w/40 in my diesel F250 since 2008 I would not use anything else!

great product

Best quality oil on the market!

Great product, price is worth the extended life and frequent changes.

I run this oil in my 2022 Duramax. This oil does not feel like it broke down at all after the 1 year change interval. I rubbed a little of the old oil between my fingers after the change, and it still felt new. I’ll keeping running it in my truck for years to come.

Just changed oil in my 2017 Dodge Ram 2500 to Amsoil 15W-40 100% Synthetic and what a difference in performance. Definitely my truck is a lot quieter and seems to have more torque. Getting ready to change my 2015 Lexus RX 350 to Amsoil 100% synthetic, these Amsoil products have really made a difference in the performance of my vehicles. A+

I have only used Amsoil Signature 5-40 Diesel oil in my 2016 Ram since I purchased it with 722 miles. I do routine oil analysis at Blackstone Labs. I follow manufacturers recommended oil change interval of 10k. I just completed the 170k change and await the lab's analysis. I usually add 1/2 qt. between changes. Amsoil makes quality lubricants that can be surpassed!

Shipped promptly, and is a great product. Unpaid spokes person.

This is the best diesel oil to use in your diesel engine....my cummins works & sounds smoother

Great product!

Works great

I’ve purchased these products for my motorcycle and diesel truck. Love it. From oil to fuel additive and gear oils. Great Product

Great product but the price is becoming ridiculous. I will probably be looking for an alternative soon.

Excellent diesel oil with max protection

Difference is unbelievably a huge upgrade in performance and protection, engine is running smoother and starts easier especially where I live it’s been 12 degrees at night even though I use my block heater I’ve noticed a huge difference in starting, before Amsoil I used only rotella t-6 full synthetic and I’ve always changed my oil every 5,000 miles, I’m a preventive maintenance person and I’ve noticed my last few oil changes the oil was really thin and it just didn’t sit well with me. I only drive about 10, 000 miles a year so it will be nice to only change it once a year.

I’ve used AMSOIL products on all our vehicles since new and have never had any issues. Would recommend to anyone

after Break-in period of a rebuilt Manufactured 6.7L started using Max-Duty and can tell it's a high-quality oil, by sound, etc.

I ise amsoil. My truck is still running. It must be working ok.

Best oil money can buy!!

I cant say enough about this oil. Its the best you can get.