Rotella T vs. Synthetic Rotella vs. Mobil Delvac 1

[KidKodiak]

I've read in many places on this forum that Rotella T is the preferred oil to use in our 6.2. I'm running standard Rotella in my 1984 M1009 CUCV. But now all my truck driver friends are telling me to run Mobil Delvac 1 because I can run it to 100k miles between oil changes.

Sounds great, and maybe the new big trucks with the newer emissions can take longer oil change intervals - but I don't believe it necessarily means it's good for my motor.

Could anyone explain why you all prefer the standard Rotella over the synthetics? I'd like to have a solid answer to give my friends.

Honestly, I'd like to run the Rotella synthetic, but would it damage my 6.2? The odometer reads 60,700. Looking at how dry everything under the hood is, and the condition of the rest of the vehicle, I believe that these are actural miles, and not a rolled over odometer.

[JohnC]

Diesels produce soot, some of which ends up in the oil. Older Diesels produce more soot. Unless you have a way to remove the soot (low micron bypass filtration, for example) you cannot extend your oil change interval without compromising durability, regardless of the oil you use.

[KidKodiak]

Thanks John. That's exactly what I thought. Do you, or anyone else have more input on why standard Rotella T is preferred over synthetic Rotella T, Mobil Delvac 1, and AMSoil Marine and Diesel?

[DmaxMaverick]

Thanks John. That's exactly what I thought. Do you, or anyone else have more input on why standard Rotella T is preferred over synthetic Rotella T, Mobil Delvac 1, and AMSoil Marine and Diesel?
Initial cost. Simple as that.

[crashz]

I'll be running a synthetic once the dump is back together. I've been thinking about using the 0w-40 that John Deere carries. Its got great wear numbers and is diesel rated (CG I think??), so it should be fine for the 6.2L. A benefit is that it will help the sluggish starts in the winter and get lube to the top end a bit faster.

Was 100K mile oil changes a typo? 10,000 is marketed for synthetics (I wouldn't do it on a 6.2), but never heard of 100K mile OCIs.

[KidKodiak]

100k miles was not a typo. That's what I was told. I'd never believe that. And even if it were accurate, I couldn't bring myself to do it.

And to be truthful, I still can't accept 10k miles for the old 6.2. I accept it for the newer, less soot producing diesels. For ours, I'm thinking 5k max.

[NH2112]

I do 5K oil & filter changes with my 7.3l, but it's got an 11 quart capacity with a PSD oil filter. My last 6.2l (and 6.5l) was done every 3500 miles.