I have had a 2007 E320 since Oct 2007. Started running B10, and gradually got it up to B100. It was at the same time few stations could be found pumping the ultralow sulfur that is "warranted" not to mention mandatory. As I travel out of the city and it is difficult finding biodiesel, I had to switch between the ultralow and bio; thus a varying net strength. I do not discount the possibility of remaining low sulfur stocks in supply storage tanks contributing to debris transferring from storage tank to car tank. The car ran fine until an incident in July when it became sluggish along the freeway and lost power. Re-gained, lost etc., and to make a frustrating story short, took it into the dealer to be diagnosed with a bad fuel pump that required replacement. Choosing the obvious path of honesty, knowing the consequences of buring higher than B5, I told them yeah I was over the limit and by the way I would like my old pump when you replace with the new $1,700. one. And yes, I know that the source of dirty fuel is irrelevant when clogging a fuel system - not warranted is not warranted regarldess of not warranting higher than B5 boidiesel.
I am now running between a B5 & B15 blend, trying to restrain myself and I have had my "old" pump torn down, surveyed, and rebuilt by a forward thinking certified Mercedes mechanic who owns his own Mercedes shop. He found some fine particles in keeping with the thinking of a batch of dirty fuel. As I understand it, the older pumps can blow a lot more through then the new ones can. I had heard from a biodiesel dealer that the seals on these pumps could be compromised by the detergent action of the bio but I suspect he may have had that confused with the older models. He did tell me he had five other calls from folks like me with this model that had to replace their pumps.
I have spoken to one guy in particular who has now replaced two pumps and has temporarily given up but he says he is preparing to have a German based mechanic, who is coming to the states soon, who has some type of retro system including a second fuel tank, to modify his car.
Why go through this? Other than the setbacks that I have had, it is a fine car. Until folks who have a little discretionary money, who can afford to push the envelope on the new models that cost more, try to turn the tide, the entire movement, while exciting and fun and reminiscent of many previous social movements in my history, will not make the difference necessary to solve some larger problems. The entire socio-economic chain needs to be shaken.
I believe, for what it is worth, that the fuel that slowed me down, was a batch from the larger manufacturer of biodiesel produced from poultry by-products rather than from the fuel I had been burning and hope to soon again which was made from used vegetable cooking oils.
That is still a large resource not taken advantage of. In the meantime, I will travel around with my re-built virtually brand new pump in my trunk and communicate with corporate Mercedes on the matter.
