Biodiesel Report: What B20 Means to You and Your Warranty

Page 2 of 2
  • Share


General Motors, which is expected to enter the U.S. passenger diesel market in the coming months, has a slightly different take, because their existing Duramax diesel engines are used in larger trucks that have long been exempt from many of the emissions standards placed on passenger vehicles. GM supports and warranties the use of up to B20 in their existing engines, but told The Diesel Driver that the varying quality in the biodiesel portion of the blend is a problem. It therefore recommends drivers use only B20 blends from suppliers that are BQ-9000 accredited, as other blends are not necessarily of a satisfactory quality.

BQ-9000 is a quality management program based in Missouri, and biodiesel suppliers may voluntarily join the program, which tests and ensures that the fuel is of consistent and sufficient quality and complies with the ATSM-D6751 standard. Biodiesel conforming to this standard is sold from pumps identified by a special label.


Illinois currently leads the nation in both the production and consumption of biodiesel. It has been a boom to local farmers and the economy, is responsible for 7,800 jobs in the state, and generated $1.5 billion of household income and $2.6 billion in Illinois gross domestic product between 2004 and 2010.  In addition, the state’s biodiesel industry itself has expanded ten-fold since 2003.

Since 2009, the state has required the use of a 2% biodiesel blend in all state-owned diesel-powered cars, and B20 biodiesel has become the rule, not the exception, at pumps around the state.

Illinois, incidentally, is not alone in its use of biodiesel fuel.  Other states that require a biodiesel blend include Alabama (5%), Colorado (20%), Florida (not specified), Kansas (2%), Kentucky (2%), Maryland (5%), Massachusetts (15%), Minnesota (B20 to B100), Missouri (B20), Nebraska (not specified), New Mexico (5%), New York (not specified), Ohio (not specified), South Carolina (5%), Virginia (2%), and Washington (not specified).

Part of the reason for the success of biodiesel is due to a favorable tax policy. In December 2011, the Illinois state legislature passed a series of tax incentives that included the extension of a biodiesel tax credit, which was originally to end in 2013, through the end of 2018. Biodiesel blends of more than 10% are completely exempt from tax and lower blends are taxed at only 80%.


While the idea of biodiesel sounds good on paper, in practice, there are many things that can go wrong.

An October 20, 2012 letter to the car columnist in the Chicago Tribune illustrates the high level of confusion when it comes to higher-content biodiesel:

“We recently purchased a BMW X5 diesel SUV. The manual states that that diesel fuel cannot be over five percent bio or the warranty would be voided. However, in Illinois, about the only diesel fuel available is 11-20% bio… Both the BMW and Mercedes dealers say its okay to use 11 to 20% bio. However, when we asked them if BMW or Mercedes would agree to honor the warranty they both said no… However, we can’t understand how BMW can sell diesel cars in Illinois without disclosing the fuel is not readily available in Illinois.”

Several months ago, the Illinois-based owner of a 2009 Mercedes-Benz R350 BlueTec reported a two thousand dollar repair bill to “clean the engine and intake manifold from the residue left over from using B20 diesel fuel for 90K miles,” pointing out that this is “the only diesel fuel available in the state of Illinois!”

Meanwhile, while the use of higher-content biodiesel fuel outdistances both automakers’ ability to assure proper functioning of a vehicle and refiners’ ability to ensure a high level of quality control, the jury is still out, to say the least.


Unfortunately, the problem of finding fuel that is compatible with your vehicle does not, at this time, necessarily have a simple solution. Some manufacturers are publicly investigating the future of biodiesel and others are wondering if they can sell cars in states where B20 is the rule, not the exception. But the major challenge all drivers and carmakers face is clear: inconsistent quality of biodiesel fuel, and mandates or tax incentives that force it into your tank. Short of driving across state lines, there is little to nothing some drivers can do, and therein lies the greatest issue, namely that an immature policy is moving towards rendering an entire class of vehicles, one recognized as an avenue to meeting future emissions standards, unusable, or at a minimum warranty-less. The onus here, in all reality, is on the government to protect its constituents but the opposite seems to be what is taking place.

Green energy initiatives sound great, but have caused problems as they have gone along. The signs point towards biodiesel being a viable solution in the future; however the technology needs time to mature.

Pages: 1 2