Amsoil and Royal Purple are good also. It's all about soot suspension, and if you got the right oil filtration, you can go months on an oil change (just be sure to send in an oil sample for analysis).

i run dello 400 and lucas oil stabilizer :jump:

If you have a Few extra minutes, read this article from a gentleman who completed an extensive oil analysis of the diesel oils on the market. This may help aid you in your decision.
http://www.turbodieselregister.com/TDR57_Oil.pdf

I'm curious about the additives. Can someone provide links to the studies please. I want to ensure I'm taking care of my truck properly.
thanks

I run Delo 400 with a can of seafoam every other change. I cut my fuel with 2 stroke oil. I only run Wix/Fleetguard filters for air (bhaf), oil and fuel (water separator delete)

Not to sound like im plugging my company but just a heads up for yall running Delvac, throughout the midwest and south all through sept. Oreily Auto Parts will be running a special on 5 gallon containers of Delvac 1300 as a harvest time special.:tu:

Thanks,
what did you read to convince you to run the Seafoam??? Is there a doc/study? I'm willing to do it, but I want data to support my limited funds...Make sense??

cummins motor oil
 

I think you can get sea foam for like 7 bucks I got a can from autozone on sale for 4 bucks...

Used seafoam in the 97 cummins and in the chevy305, they both loved it. Direct injection for imediate cleanse and pour the rest in the tank for total cleanse. Shell smoke for a bit...till they clean out. Make sure you have good ventilation.

Looks like im buying my oil at napa :) notice how close castrol and motorcraft were. it sure looks like ford oil is castrol

Mystik JT-8
Motorcraft 15w40 or
Valvoline Premium Blue 15w40
Rotella 15w40

CANNOT go wrong with those three.
One thing to consider is Motorcraft 15w40 is CI-4 rated, and it contains more Zinc and anti-wear additives since 99% of diesel oils on the market now are CJ-4 rated.
Sounds funny to run a "Ford" oil in a Dodge truck, but oil is oil- difference is the Motorcraft has more of the good stuff!! That is my non-technical explanation so you all do-not get bored reading!!

One major benefit to the motorcraft other than the heavy treatment of anti-wear additives is the high starting TBN. It starts out with a TBN of 14.
TBN stands for Total Base Number, it controls soot.. fuel.. and other contaminants which cause the oil to become acidic. Simply put, Motorcraft 15w40 has a 30-40% increase in TBN over other diesel oils. It's a long story, but this oil was designed for the 6.0L Superduty before all of the emissions crap came out in 2007/2008 so they still make the oil as CI-4.

One of the little known secrets in the world of diesel motor oil.
And you heard it here.. if you take advantage of it that's up to y'all. :tu:
Just make sure you get the bottle that says CI-4 [Charlie India-4]
IF you can find the red bottle of Motorcraft 15w40 with a CI-4 rating consider yourself very luck, as all CJ-4 rated oils have the level of additives cut way down.
Another good one is Mystik JT-8 15w40, it's a synthetic blend available at most farm stores / autoparts stores.

Truth is if motorcraft weren't available and I could FIND the Mystik JT-8 I'd prefer to run that.
JT-8 is also not as well known and it is one of the best available.
It's a synthetic blend with a good additive package for the same price as regular delo/rotella/ect!!

Looks like my local Advance auto now stocks Mystik JT-8 in 2 Gallon jug for 29.99 and they also stock Mystik synthetic blend gear oil for $4 a bottle.
Guess my differentials are getting fresh gear oil too!!

#1 pick Mystik JT-8 15w40/15w50
#2 pick Motorcraft 15w40
#3 pick Valvoline 15w40
#4 Rotella