Interesting thread; I just wanted to interject that biodiesel is not available in all parts of the USA. I haven't seen any in eastern PA. I have seen it in VA but that is far. So I am running Sheetz ULSD at 3.529 a gallon. :eek:

But this ain't Germany and we don't have that sort of QC here for Bio.

But if the biodiesel is not done properly, well..... With the prices of the components, you can see why MB is going to be hesitant about you running anything above B5. Now, if we could get the QC to be done like in Germany, no problem. Also, what if you made your own biodiesel and you made a B50 batch of fuel and it was bad? There isn't enough D2 to drown out the biodiesel.

Great link from Mercedes Benz Club of America
 

After lots of surfing, I found a lot of useful info here.

http://mbca.cartama.net/showthread.php?p=122082&posted=1

Chris Powers at Houston Biodiesel sells ASTM D6751 spec biodiesel. He only sells it in B99 blends though. If you want it bad enough, you'll have to fill the tank up with ULSD (assuming you have a 20 gallon tank), drive around and burn a gallon and then add some B99 to top off to make B5. Not really worth the hassle if you ask me, driving from one station to the other to make a blend like that.

We do have quality check standards, its just not mandated. Here is how to understand ASTM test results.

http://forums.tdiclub.com/showthread.php?t=110004&highlight=biodiesel+pd

People just make things more complicated or harder then it really is, its not hard to ask for the test results and check. If the results are good the fuel is ok in your car, if the test results just barley meet the standard or just suck then run it at your own risk.

simple dude

You are not mistaken on lubricity but you are about engine longevity. Your engine was designed to use ULSD so there really isn't much benefit to BioD for it.

If it isn't mandated, how does the company know whether you are getting the good stuff or not? If not, why should they warranty your car?

True. However, when it is under warranty, you are running it at THEIR risk. Again, why should they take the risk?

The vendor (unless he is getting it from some guy making it in his garage) will always get the ASTM test results for the biodiesel being pumped into the tanks that they have to sell to their customers. The same with gasoline or diesel, you can always ask the station for the ASTM test results for the diesel or gasoline you pump into your car. You can get a bad batch of diesel that will screw up your engine just as much as biodiesel.

My moms passat TDI doesnt take kind to crappy fuel, it will run like *****. We have gotten a bad tankfull of diesel from a beacon station, the engine idled terrible, fuel economy was bad, made it harder to start and ended up clogging the fuel filter. Soon after we put in diesel from the chevron station we normally fill up at and everything was back to normal. We decided never to go back and buy fuel from them.

But your point is valid, why should Mercedes Benz take the risk of the customer getting bunk fuel and screwing up the expensive fuel system? They shouldnt!

But thats not to say that properly made and tested biodiesel fuel will hurt the engine or fuel systems. Which is why i stress that if you are going to run biodiesel over the B5 limit in any late model diesel make 100% sure that the fuel has been tested and passed the ASTM test.

Otherwise YOU run it at your own risk and YOU are your own warranty, NOT Mercedes Benz.

In the last episode of Top Gear (Season 10 episode 09) they used 500 gallons of home made rape seed BioDiesel in a BMW 330d and ran it in the Britcar 24. Before the race even started they said the crankcase had fuel in it after too much methanol in the fuel ate the pump's seals.

I agree 100% that properly made and tested biodiesel is fine in the car. I'd run it myself if it was appropriately priced.

Problem is most people don't do that until it is too late. Then they ***** that MB won't warranty the repairs.

Obviously, it wasn't properly made and tested. Like Greasybenz said, use at your own risk.

Someone didnt properly wash the biodiesel! Thats to bad, the methanol probably toasted the engine.

After the warranty is up, experiment with burning whatever you want.

But WHY would you experiment with a non-specified fuel while the car is under warranty? The mere (and maybe remote) possibility of being on the financial hook for replacement injectors :eek: or the very complex emissions system :eek::eek::eek: while the car is under warranty is too much of a risk!

MB would be 100% correct in rejecting any potential warranty claim if you were obviously not following manufacturer instructions!

exactly.. My friend's TDI is out of warrenty so its running B100 without an issue and the new ML320 CDI is running the limited B5 just fine.. He doesn't want to push his luck with the Benz.