Actually the majority of diesel these days is often a bio blend, All the major truck stops sell blended fuel. If you look on the pump you'll normally see a B5 or such sticker stating the biodiesel blend percentage. According to Mercedes-Benz like other manufactures, B5 is ok but above B20 they take issue. The recommendation is to use places with a high fuel turnover rate like a truck stop as the fuel spend less time in the tanks. Biodiesel has a shorter shelf life than non-blended diesel. In colder climates the limit is B5 due to increased cloud point or "gelling" (the paraffin wax in the fuel congeals and clogs filters) of biodiesel. If you are traveling around the county you need to fill up with "winter blend" before venturing into the colder regions . Snow birds have this problem when they fill up in Florida and then return to chilly Michigan and their class A stalls out from a clogged fuel filter. Blends of B5 of less do not require labels (https://www.law.cornell.edu/uscode/text/42/17021) Since the Fed's offer incentives to use biodiesel, many retailers blend to 5% or less so they don't have to label the pump as biodiesel and yet get their tax credit from the Feds. (http://www.natso.com/blog/truckstop-bio ... unraveled-)
Source: http://www.biodieselpumplabels.com/
From Mercedes-Benz: http://www.mbusa.com/vcm/MB/DigitalAssets/pdfmb/serviceandparts/biodiesel_Brochure5.pdf
Diesel fuel with up to B5 biodiesel content according to ULSD specification ASTM D975 meets Mercedes-Benz approved fuel standards and will not void coverage under the Mercedes-Benz New Vehicle Limited Warranty. Diesel fuels between B6 and B20 or higher pose risks of engine and fuel system damage, and are not approved by Mercedes-Benz. Please refer to the following recommendations to help avoid engine and fuel system damage if you do not have the chance to refuel your vehicle continuously with ULSD, maximum B5:
• Fill up with ULSD (B5 or less) whenever possible, from a name brand fuel station.
• Regularly monitor your engine oil level if you have no choice but to use B20 fuel.
• Strictly follow the oil change intervals quoted in the instrument cluster and within your maintenance booklet, and use ONLY engine oils and filters approved by Mercedes-Benz for use in the vehicle.
• If you do not plan to drive your vehicle for several weeks, fill your vehicle’s fuel tank completely in advance with ULSD fuel.
• Limit engine idling time to five minutes or as mandated by local ordinance.
Fuel with biodiesel content greater than 20%, including B100, is not approved by Mercedes-Benz due to the risk of severe engine damage. Any damage caused by the use of such non-approved fuels will not be covered by the Mercedes-Benz New Vehicle Limited Warranty.
Use of higher than B20 results in higher (cylinder wash) lube oil dilution which requires more frequent oil changes.
