Here's an interesting article about Biodiesel and a potential issue with how it competes with ZDDP (anti wear agent) inside an engine.

It's a faily old report and mainly directed towards post injection engines, however we all know that the 6.0 is capable of leaking some % of fuel into the engine oil.

Here's a copy and paste:

It didn’t take long for Fang to discover the adverse effect aged biodiesel has on ZDDP, the anti-wear additive. ZDDP is chemically designed to be attracted to the metal surface of the cylinder walls and to form a protective layer. “But if you’ve got biodiesel in your oil, and the biodiesel likes to go to the metal surface too because the metal surface is polar, the biodiesel competes with the additive over the metal surface,” Fang says. Although there are complex interactions between the biodiesel and additives affecting the functionality of the additive, Fang suggests the mere fact that biodiesel and ZDDP compete for surface area on the cylinder walls is troublesome enough. The effectiveness of detergents is also mitigated by the presence of biodiesel in the oil.

Copy and Paste:
Even though for years biodiesel has been heralded as a lubricity additive helping keep fuel system components like the moving parts inside fuel injection systems operating smoothly, the bitter irony here is that, when post-injected, it tends to dilute engine oil and interacts with additives and increases the possibility of engine wear. Much work remains developing viscosity improving, anti-wear, dispersant and detergent additive packages in which adverse reactions with biodiesel are significantly reduced.

Understanding the Post-Injection Problem - Biodiesel Magazine

 

Interesting post Troy!

I have suspected for awhile that either my biodiesl additive (B2 concentration) or my Stanadyne has caused my slight increase in iron in my engine oil. I have never had bad fuel dilution or moisture content in th oil, but there always is some!

As a test - I have a few bottles of ZDDP to "spike" my oil with (next change) AND I have currently quit using bio for this oil change interval.

I hope my future UOA results are interesteing!

 

Excellent... Please report your results!

I do run B5 from time to time but haven't done any oil analysis to confirm it's a problem for iron wear or not.