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Comment Re:Well of course (Score 1) 584

whilst biodiesel would certainly make us less dependent on oil, it still isn't a long term solution for environmental problems, seeing as the emissions are as dirty if not dirtier (higher micro-particle count, etc). the leading automobile association here (Germany, ADAC) advises not to use biodiesel in modern diesel cars. I forget the technicalities, but some components get clogged from the thicker and less pure biodiesel, forcing a more frequent exchange of these parts and shortening the life span of the vehicle.

You must have missed the part where I said that I own (or rather, my girlfriend owns -- same difference) a diesel car. Because of that, I do know these "technicalities." ; )

First of all, regarding emissions: Biodiesel has the distinct advantage (over both petrodiesel and gasoline) of being carbon-neutral. In other words, all the CO2 released from burning it is CO2 that had recently been in the atmosphere anyway (before the plants from which the biodiesel was made absorbed it). It also does not produce more particulate emissions than petrodiesel. Finally, biodiesel produces zero SO2 (but with the change to ultra low sulfur diesel (ULSD), that's no longer a problem anyway I think).

Second, there are two major known possible issues when running biodiesel blends above B5 in a modern "clean diesel" (in this case, a 2009+ Jetta):

  • Biodiesel might work its way past the piston rings and contaminate the oil, causing the need for more frequent oil changes (keep in mind we're talking about 5K or 10K miles instead of 20K+, when using the correct (VW 507.00) synthetic oil).
  • Biodiesel produces different kinds of particles which may clog the diesel particulate filter (an extra exhaust system component that goes between the catalytic converter and the muffler) more quickly, causing more frequent regen cycles and possible premature failure of the filter itself only.

Of course, the real reason that VW doesn't warrant the use of biodiesel blends over B5 in the new cars is because it doesn't want to be liable for any unknown problems. There are people testing biodiesel in the new Jettas, and they could very well discover that biodiesel is perfectly OK. It's just that nobody knows yet.

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