I"ve been making my own bio for 5 years now, and running it at 90% in two of my duramaxs and one of my 6.5 turbo diesels....have never had any problems at all. it all depends on how you make it i went to school for a week on how to properly make bio from one of the leading experts that sets up the constant flow bio plants around the world.
2004 Duramax 320,000 miles
2001 Duramax 235,000 miles
1993 6.5 turbo 215,000 (8000 on new jasper)
Ride on Spreaders/Sprayers