the last issue of Volkswagen’s DasAuto Magazine, the “Ask Volkswagen”
segment answered one of the most common questions I hear Volkswagen TDI
owners ask. This as to do with how their TDI diesel vehicles run
alternatives to petroleum, be it be SVO, WVO (Straight or Waste
Vegetable Oil) or biodiesel. The “Can I use biodiesel in my Volkswagen vehicle?” is a popular question. The answer has always been ‘yes’ with a but …
Volkswagen only recommends a 5% blend of biodiesel to petroleum diesel fuel.
Of course this is the official “company who has to stand behind the
warranty” answer. A more appropriate answer has to do with just how
well VW TDI engine tolerate biodiesel long term and what potential
risks can be minimized. For example, there are many example of older
Volkswagen TDI have used high percentage “quality” biodiesel for
thousands and thousands of miles. The key word is “quality.” Biodiesel
that is properly manufactured, washed and filtered has little ill
effect even in higher percentage blends in all but the Pumpe Duse TDIs.
(mid-2005 and newer TDIs had higher pressure PD injection systems that
“could” see problems with high percentage biodiesel — this is
speculative opinion) Also the new ‘clean diesel’ 2009 and newer TDIs
might also have emission control issues with higher percentage
biodiesel … their particulate filter exhaust system might not be able
to handle high percenage biodiesel exhaust?
That said, biodiesel is still being successfully used in many VW TDIs.
Here’s a list of a few items to consider as you increase your
percentage blends — but for the record, Arthur Daniels Midland and VWoA
is said to be testing B20 (20% Biodiesel) in VW TDI diesel engines.
Times are changing and I suspect that it won’t be long before most manufacturers approve the use of a B10 or B20 fuel and warranty its use.