biodiesel and warranty question

aloha! i'm about to buy an '06 turbo diesel new beetle. i really want to use biodiesel, but a friend said that she had heard that it may affect the warranty. in other words, if you bring it in for repairs and they discover that you have been using biodiesel, they may not fix the car under warranty. has anyone heard anything about this or know if it's true?

  You would have to go to a dealer and find that info, However
  biodiesel isn't suppose to void the warranty. It is formulated to
  conform to factory specs.

I agree with smoking dog on the warranty issue. Check with a dealer. If you plan to use old cooking oil like some, I recommend you research this carefully. I have a 06 Bug with the TDI and it gets 38mpg city and about 50mpg highway, so I wonder why you would want to do this.

    You know it, trying to save a few pennies may cost you some
  dollars. Just like adding alcohol to gasoline to streatch it, you
  will have more gallons of fuel, but alcohol get about 1/2 the
  miles per gal, so you've backed up instead of gaining.

I keep seeing people that say their dealers won't honor warranties on vegetarian VWs, however VW and ADM (supermarket to the world) like this combination - here is a link that may be worth reading ...
http://www.biodiesel.org/resources/pressreleases/pas/20050318_VW_B5.pdf  --
I do remain skeptical on content of most articles until I can verify the authentic author - big oil makes their money of foreign supply, not American farmers -  The American groups are fighting to get in, so who will say something to hurt the other OR bolster their own business... Just don't go adding cooking oil from your kitchen, as the glycerin WILL CAUSE PROBLEMS... you need to be sure to buy tested good bio fuels, and like others above have stated,  it is formulated to run in the car.  Let's not forget that Rudolph Diesel designed this engine 100 years ago to run on peanut oil.

Finally, I've read VW's remarks from 1994 to present, and their only objection is Bosch won't comment on compatability with veggie oil.

I have been running biodiesel in my New Beetle TDI for 4 years.  Some friends do straight veggie oil or SVO conversion kits to run in their VW's which heats up the veggie oil to a temperature where the oil runs like a liquid.  But, I saw a friend lose his engine in the winter because he got impatient and switched over to SVO to soon before it had a chance to heat up properly.  I have been running B20 in the winter with temps going down into single digits and it starts right up.  In fact I have some homebrew bio-D that is outside in a bucket and with 20F was still liquid.
 
VW warranty covers 5% biodiesel use.  America does not yet have a standard for biodiesel and quality varies from one maker to the next.  Most commercial producers have ASTM certified fuel but, home brewers do not and VW can't prove where your fuel came from.  In America soy is predominately used where as in Europe it is rape seed oil or canola ( a modified non-poisonous to eat form of rape seed).  Canola is actually better than soy because it will not pit aluminum parts in the engine like soy, but like stated earlier ADM has their hands in what food stock biodiesel is made from. 
 
Just a tip, VW does not have the time to test what kind of fuel is being used so if you don't tell them they won't know just make sure you put regular diesel in before you take the car in.  Of course the aroma of biodiesel will give it away if you bring your car in with a tank of bio-D.
If they determine that engine damage was caused by fuel you may be out of luck.  VW's are, from the factory, biodiesel ready and is used heavily in Europe and VW group of America will automatically blame bio-D. 
 
Sorry for my ramblings but, I keep having to leave and come back to writing.