UOA for biodiesel fueled TDIs

[maktas]

I have searched the threads for problems associated with engine oil "dilution" while using bio-d, however, I could not find anyone else's UOAs that can provide evidence of this problem. Does anyone have info regarding this issue of dilution while using bio-d?

 

[Revolutionary_mind]

Are you talking about waste veggie oil? Or B100?

 

[maktas]

Are you talking about waste veggie oil? Or B100?

B-20 to B-100, ASTM biodiesel, made from waste veggy oil or virgin stock, homebrew or commerical. I am not interested in UOAs of people using SVO.

 

[EddyKilowatt]

I don't have the UOA numbers handy, but I ran commercial B99 (claimed ASTM) for a 12kmi OCI with Delvac, and didn't see anything alarming in the subsequent UOA, specifically not anything that looked like either dilution or polymerization. (Not that I'm an expert on UOAs.) I think dilution is a problem that varies *a lot* depending on condition of engine, fuel system, and drive cycle/driving conditions.

I *did* do an injector nozzle swap shortly after that OCI, and the comments back from the guy (club guru) who shimmed and pop tested them included "heavy varnish", "needle scoring", and "is this a biodiesel engine?".

Concurrent with that, my B99 supply failed a couple of pHLip tests... so I am back on D2 for the time being, awaiting further developments on the biofuel front.

But the UOA seemed fine. I'd offer to dig out the records but they're in storage at the moment.

Eddy

 

[Mrrogers1]

I'm tagging in here as I too would like to see some UOA's for Bio blends or B100 Jetta's. I have an oil change coming up and it'll be the second since I've owned the car and the first full interval with Bio. I have been running between a B10 and B20 mix over the last 5k (I'm setting a benchmark for extended change intervals so no comments on 5k changes ) and will actually be doubling that in my 06 over the next UOA for sure. (Our Coop is coming online so I'll start running 5g per tank)

I'd be interested to see if anyone has seen the dilution that we hear talked about and I at what blend it is being seen.