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

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

I use 5W-40in my 3VW TDI WHEN I TOOK a trip to AZ 122 temp I seen my oil in my Commons diesel pick up to literally evaporate the oil. In Wisconsin, my truck doesn't use any oil. In outer Arizona, it evaporates the oil.

This is the only oil that I have found that does not cause me problems with my diesel exhaust filter. No regens since I have been running it. Ram 1500 ecodiesel.

We used to run Amsoil in oil fleet vehicles years ago, don’t know why they got away from it. Anyways, I run a 2019 Chevy DRW, bought it with 92k. First oil change I did, went with Amsoil Signature. Went to oil change interval recommended by GM (approx 7k miles). I tow a 14-16k 5th wheel light/ moderate distances several times a year. Had the oil tested by a 3rd party, analysis came back I could go to 10k. Levels tested still well above normal for oil with the mileage and oil filter was still good. Don’t know how they could test that, but they did. Went 10k miles on next interval, had it tested again, same tests, same company. Analysis came back less than before, but still above acceptable levels according to them. Have a sample from 15k miles waiting to be tested. I can say, all of my vehicles now use Amsoil signature!

run this in my generator for a peace of mind knowing it's the best

Best oil

I have been using this in my truck for 27 years and my truck still runs great. 352,000 miles.

This exact oil saved a motor that blew a head gasket and lost all but 2 of the 14 quarts. Ford mechanic was amazed at how good the cylinders still looked. He stated he had many that had the same problems but all the others the motor was trash. Mine just had to have a new head gasket engine flush fresh oil and antifreeze. Then was back on the road.

This oil is the only oil I’ll use on my diesel truck!! She’s 11 yes old and runs like a champ