Let's hear it

The one with the correct API and weight rating. Really isn't any bad oils out there, When I had my Power Strokes I've used both Rotella T5 and Motorcraft Synthetic. Never noticed a difference.

Unless you've deleted the DPF, anything that has a low ash rating is recommended!

This. Same for gas. I pretty much run supertech in everything, including diesel ag equipment.

Waiting on the Amsoil bandwagon to chime in on how superior their oil is...

Usually its a sure bet they sniff out posts like this on the fist page.

Some of their stuff could void a warranty because it doesn’t actually have the license.

I have been using 15 40 Rotella for 25 years in all my Cummin's Dodge's. Never a issue for me. Change oil and fuel filter every 10,000 miles always. This one is 2012 deleted. I have had 5 of them. Oil comes out almost as clean as when it went in.

amen buddy

My 2006 Duramax LBZ has seen Mobil Delvac 1300 Super for 327,000 miles. No issues with it at all.

Take that back, I tried Rotella T4 in it one time and it got the classic “typewriter tick”. Delvac has never caused that

I use CAT 15-40 Ultra Low Sulphur in my 2006 Duramax. Has served me well for years.

I've owned a ton of diesel's over the years, for Cummins and Powerstroke I've run Rotella, Dmax liked Delo better. For the farm equipment It's whomever had the best deal on a 55 gallon drums at the time, I think right now we have Rotella on tap. I've used Royal Purple in the past and it seems to do a good job but it's seldom available to our bulk oil distributor for whatever reason.

15 40 Rotella for 05 Duramax w/328,000.

I know nothing about Amsoil but I do use it my Harley because two reputable independent Harley shop owners use it in their personal bikes. Each own several...that said so far so good. In my SD with 6.7 I use what Ford and the dealer recommends and I see nothing to lose in using these. I am thinking if they are inferior my warranty would be [censored]. That said I do change around 6k miles. In my Honda accord I use whatever full synthetic is on sale. I am not convinced there is a great difference in oils unless you are comparing the difference in dino or synthetic.

I have used Rotella in my Ram Ecodiesel and now in my Ford Powerstroke. Always T6 full synthetic. Zero issues. Ford manual says 5W-40 for full operating range, so I can't use 15W-40 unfortunately.

When I had a Duramax, I used Delvac in it after going to Rotella and getting the ticking noise. Never had an issue with Delvac in it.

Diesel engines are too expensive these days for super tech IMHO, although I did use Super Tech for years in my Silverado/Sierra 1500 vortec motors without any issues.