BIofuel in Jetta sportswagen

I recently bought a 2011 Jetta Sportswagen TDI which I would like to start using biofuel in, even if only in a 5-20% combination with diesel fuel.
The biofuel stations say this is no problem even at 100%, the dealer recommends no more than 5% and two mechanics I have talked to said I will ruin my engine by using any biofuel. Has anyone tried any of these combinations for long enough to know what problems might develop? What say you, Click and Clack?

Follow the dealer’s recommendation. Problems = $$$$. Don’t rely on other’s opinions, VW is the authority here.

And make sure the ‘bio’ part of your diesel is not from tropical sources, thousands of acres of rain forest has been razed to grow palms for biodiesel. A true ecological disaster.

  1. Click and Clack have retired from the show, and don’t monitor this wbsite in any event. You get interested professionsl and amateur mechanics answering here.

  2. Your TDI is a modern, common-rail, elctronically-controlled diesel with emissions–which is another way of saying it’s particular about the fuel it gets. What you want for bio-diesel (or WMO, don’t forget that) is a big, dumb, mechanically-injected deisel from the pre-emissions era–back when diesels were fuel-efficient, reliable, and sooty. A good 6BT from late last millenium would do nicely.

What does your owner’s manual say? You didn’t tell us that.

B5 (5%) max biodiesel per VW:

“In an e-mail message discussing the new TDI clean diesel technology, Steve Keyes, Volkswagen’s director of public relations, stated “All Volkswagen TDI models are warranted for the use of up to a B5 blend. Blends of biodiesel higher than B5 void the Volkswagen warranty.””