Diesel Oil.....

Durb - I agree with you, I rather have clean oil than older high mileage oil.

I run Rotella T6 year round because I need it in the winter where I live. If you're in a warm climate the standard stuff should work fine and it would save a little bit of money. T6 is pretty cheap on Amazon, though, and I think there's a rebate right now.

I use Delo 400 in my 5.9, buy it on special at Costco. However, I change my oil at smaller intervals than most as the process is simple and relatively inexpensive. I may be wrong, but in my mind, clean dino oil may be better for my engine than dirty synthetic oil. If I had a bypass filter, I would run synthetic with longer intervals. Since my truck has low miles, I can't say anything quantitatively about longevity.

I run Shell Rotella T-6 in my 5.9 because it is a superior oil and right now they have a discount/rebate going on.
Bill

^Does the regular dino Rotella still smell?
I don't typically run that because it used to smell like you had an oil leak on the exhaust.
Have t tried it in a long time, but run T6 in the wet clutch bikes and SRT

For the engines that DON'T require the newer "LE" low emissions formula AMZ/OIL still makes their 15-40 Diesel Marine oil.

I would run that 10k in my 98 12V with Blackstone report saying to try 13k next time. I changed every 10k just because it was easy to remember and i bought 55 gallon drum at a time.

I use whatever is on sale, but mostly Valvoline blue. The important part is that you maintain the truck, not which brand of oil you use. IMO

I know nothing about this 5.9 that I just bought, except it really runs good.

I've always used Delo 400 in diesel engines, what do you prefer and why?

I use Shell Rotella. But, my understanding Delo works, also.