About our campaign issue

2007.5 and newer light duty diesel vehicles are not biodiesel compatible! Problems have occurred in these vehicles using biodiesel in any blend, from B5 to B100. This is shocking news for everyone involved in the biodiesel community, including producers, retailers and their customers, city fleets that use biodiesel, and all diesel drivers in cities that have B5 or B20 mandates. If not addressed, new vehicle incompatibility will increasingly cripple the viability of biodiesel as a cleaner-burning and renewable diesel fuel alternative.

How did this happen?

New and more rigorous emissions standards from the Environmental Protection Agency (EPA) and the California Air Resources (CARB) require the incorporation of a diesel particulate filter (DPF) to trap emissions. The issue of incompatibility arises not from the DPF, but rather from the injection process used to create an exothermic reaction which thereby burns off the soot from the combustion cycle. The resulting ash is then caught in the DPF.

The majority of original engine manufacturers (OEMs) are using a "late post injection" process, in which a small amount of fuel is injected directly into the cylinder post-combustion. Because biodiesel has a higher flashpoint than petroleum based diesel, it does not always fully vaporize during this process, and some droplets can remain in the cylinder in liquid form. That unburned fuel adheres to the cylinder walls and makes its way past the piston rings into the crankcase, causing engine oil dilution.

A small amount of engine oil dilution does not destroy an engine right away-- especially in the case of biodiesel, which is a much better lubricant than petroleum diesel. However, if too much contamination accumulates in the oil, the crankcase can become overfilled, causing catastrophic engine damage. Mild oil dilution may also lead to long-term engine wear, although this has not been fully tested yet.

Click here for a more in-depth discussion of this problem, including a list of references.

What can be done to fix this problem?

The good news is: there are other ways to use DPFs without risk of engine oil dilution! Instead of post-combustion injection into the cylinders, the OEMs should be using an exhaust stream injection process to regenerate the DPF. Exhaust stream injection involves injecting fuel downstream of the combustion chamber, between the engine and the exhaust. This is what Caterpillar is doing in their heavy duty equipment.

Most OEMs (including Volkswagen, Ford, GM, and Dodge) are currently using biodiesel-incompatible technology, and they won't change that without public pressure. That is why SaveBiodiesel.org has launched this campaign, to tell the OEMs that new diesel vehicle emissions systems must be compatible with biodiesel, and to ask the EPA and CARB to require it. Please sign our petition, and then learn about other ways to get involved!

If you want to use biodiesel in a 2007 or newer vehicle, please visit our frequently asked questions page. While we do not necessarily recommend it, there are some ways to minimize your risk and/or inhibit the late post injection process.