Actually, we didn't say to stock up on oil filters, we said to stock up on fuel filters. That is because of the common issue of clogged fuel filters due to poor quality biodiesel.

The real issue with biodiesel is that the spec says how much it bio (5, 10, 20%, etc) but after that, there isn't much in the way of specifications. Different bio diesel blends can have very different characteristics, it is very open.

Properties that typically vary include density, kinematic viscosity, heating value, and cetane number. It all depends on the feedstock, and it will vary from crop to crop and with the same crop, over time, due to weather conditions when the crop was grown.

Yes, it can burn fine. Or it can be a disaster. If you have a trusted source, and haven't had any problems, then you are less likely to have future problems with fuel from the same supplier, as long as they get it from the same source. But the reason BMW says not to use it is because they, you, and the supplier of it, all know very little about what is actually contains, most of the time.

To compare it to lube oil, which is very standardized as to quality, cleanliness, performance specs, etc, it is like saying that you are going to use oil that comes in blue cans, without having labels that specify viscosity, lubricity, performance standards, etc. Might be fine. Might kill your engine. You will know after you have used it for awhile. Is it worth the risk?

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue