Customer Ratings & Reviews

Amsoil is the only oil I put in all my Diesel engines. I love the next day delivery I will be a lifelong customer

No oil beside AMSOIL Heavy Duty makes my truck run the way it does.

I use amsoil in both diesel trucks and in my diesel welding machine

This "magic" oil reduce by half the engine oil consumption of my truck!!

Great product been using it for years

I’ve been using this stuff for a few years now on my Cummins and I strongly believe this is the best oil on the market.

I use Amsoil in my cars and motorcycles and just tried in my semi truck. Can’t believe the difference over other major brands. I was disappointed major brands because I do long oil intervals changed with my ops filter and oil test every 25000 miles. The major brands I couldn’t keep the base up to where it needed to be. I will update on my lab test on Amsoil after 25k . Plus my fuel mileage went up one tenth. We will see if this continues

Will use anything else

Switched over from Royal Purple and could not be happier.

All usual Amsoil doesn't disappoint. Great oil for Ram 6.7, and there deliveries rapid. Will always buy my oils from Amsoil

Worth the money

Quality stuff here. Long lasting good quality oil. A bit pricey but you get what you pay for

Use Amsoil Signature Series Max-Duty Synthetic Diesel Oil 5W-40 for every oil change. Rated the best for Cummins diesels.

This is just outstanding oil.

Car seems to run more smoothly

Good stuff!

Surprised, a lot smother and quitter engine

I have been using the 15 W 40 Amsoil diesel oil for many years on different GMC Duramax diesels. All on lower mileage trucks. It is a good durable oil. No burning of loss of oil. No engine mechanical issues. I perform the oil changes myself. Libricity of the old oil is very good. The 2.5 gallon container is difficult to handle without spilling. I recommend getting it in quart size containers. I recommend the oil.

Great oil at a good price. Overnight delivery

This product is spectacular, immediately noticed improved performance in my truck and I would not use any other brand besides amsoil for diesel engines!