All major Original Equipment Manufacturers (OEM) approve the use of up to 5% biodiesel (B5) when blended with diesel fuel that meets the appropriate CGSB and ASTM standards. BQ9000 accreditation is specified by some OEMs. Cummins has approved all of its engines for 7% biodiesel blends.
Millions of diesel vehicles run mid-level blends (B6-B20) every day with full operability and billions of successful US and Canadian road miles over two decades. Engine manufacturers are full participants in developing the strict biodiesel quality standards that enable the use of blends up to 20% (B20). OEMs have been party to widespread commercial use of B11, B15 and B20 in several US states (e.g., Illinois, Minnesota) and neither they nor other stakeholders have reported any more incidence of engine or operability issues than is found with straight diesel.
Truck manufacturers have not intervened in markets to disapprove regulations and incentives for mid-level blends. Strong fuel quality oversight, and an experienced petroleum sector, has been important to mid- level blend success, including BQ9000 fuel quality accreditation and the adoption of inline biofuel blending capabilities.
OEMs express warranty approval only for models that have been tested on biodiesel blends; this is common for late-model engines. When an OEM does not express biodiesel approval for an engine, it means only that biodiesel testing has not been conducted on that engine. Manufacturers mostly do not test legacy models; they are ‘out the door’, with biodiesel testing conducted only on new models.
Lack of warranty approval is sometimes mistakenly taken to mean that an engine will not be operable above the warranted blend level or that warranties will be voided for use above the stated level. This is not accurate. Where an affirmative warranty statement has not been given, the OEM has not specifically tested that model.
A joint statement by the Oregon Auto Dealers Association and the Northwest Biofuels Association explains the Magnuson-Moss Warranty Act (MMWA) for biodiesel in the simplest terms:
“A vehicle’s warranty cannot be voided solely due to the use of biodiesel. Even if the manufacturer recommends a blend of 5% biodiesel and a customer uses a higher blend such as 20% or 99% biodiesel, this does not void the warranty. If a customer uses a blend of biodiesel that is not recommended, that in and of itself, does not void the warranty. If the biodiesel is not the cause of the engine or parts failure, the warranty must be honored (assuming the failure is not the result of another external factor).”