Very good quality.

Boatload of additive for Excellent TBN analysis between extended oil changes.

I use this in my 98 Dodge Ram 2500HD with the 5.9L Cummins 24v engine. It's been great to the engine.

This motor oil is used in my F250 work truck. I've been using it for around 130,000 miles

Great lube. Have used in gas and diesel motorhomes

Great product. I have used this oil in this truck for 20 years. I find it runs as good as the day that I bought it.

2004 Cummins 5.9 300000+ miles still has cross hatch in the cylinders

I use this oil in my 2006 Duramax with 180,000 and my 2006 Mercruiser. Oil works great.

I use it in my Chevy gas trucks one has over 307000 miles on it never been into it 5.3L LS

Great oil, I have been running this in my 2500 4x4 dodge diesel for 10 plus years. 302,000 miles on it. Also use it in my Kubota Tractor, run it for 15,000 miles per oil change, change oil filter at 7500. I have sent the oil to lab several times, after 15,000 miles running time, oil always comes back good, never breaks down, good product,

I have gotten great results with the oil. Have gone 40,000 miles on my oil changes. And I am taking baby steps towards 100,000 miles and beyond.

Freat

I use in my 2001 F350 powerstroke on pull 35 ft 5th wheel.

15w40 AME & a 15micron Donaldson P551018 for my annual oil/filter changes. From Southern summers to Northern winters, UOA shows that this combo can't be beaten for my over fueled, compounded decathlete 12v Cummins. Don't ever stop making this outstanding CI4+ oil.

Been using since 2003 in Duramax. Handles all climates.

Switched to amsoil in my 2006 f250 powerstroke. My truck now starts much better, and runs quieter and smoother!

Only oil I've ever used in my 6.7 Cummins for last 100k aside a rotella hear and there. Also use the amsoil oil filter. Works well together !

I've run Amsoil in my 05 Cummins 5.9 for around 200k. And I've used all the different diesel oils Amsoil has to offer from highest of performance to the eco price. But In my leaky 300k plus and climbing work diesel. the marine oil always comes out with just about as much as I put in 10k ago. And the others I would sometimes be up to 3Qt short when drained. Like it's gets so thin that it finds completely new ways to seep out !! But that why I like to order the heavier oil. Lastly my whole truck runs on Amsoil rears,difs,transfer and engine, and I strongly believe that Amsoil is the soul reason why my Cummins runs as good as it does at 310k miles!! Thanks for the spectrum or synthetic lubes to chose from!! Two thumbs high from this guy!!

Amsoil heavy duty 15w-40 marine diesel oil has proven to me that it will protect my Cummins engines. I have older high mileage Dodge trucks that get driven on the highway, gravel roads in -15F cold and 100F heat and the lab results from my oil samples have continually came back great. At a minimum I put double the factory recommended mileage on this oil before changing, depending on driving conditions.

Reduced engine noise (duramax)