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Reader Question: Biodiesel in a new 2008 Ford F-250 Pickup?


2008 Ford F-250 Super Duty King Ranch right front

2008 Super Duty King Ranch.

photo © Adrian Gable

Jerome writes: I just bought a Ford F-250 2008 Diesel, specifically because there is a biodiesel station near my home in Sebastopol, CA. I have heard a lot about the ability to use or not use biodiesel in the 2008 Fords. I asked the service manager at the local Ford dealer, and he said that it would void the warranty. I asked him if there was anything specific about the new Ford compared to other manufacturers that would make it more susceptible to issues with biodiesel, and he said no ... he could not comment further. It seems that the main issue with using biodiesel is making sure that the fuel is properly distilled to make sure that it is of high enough quality. That seems to be the real issue. Would you agree that if I am getting my fuel from a good producer, that meets the ASTI recommendations, that I will not be putting my truck engine in danger with going to higher levels of biodiesel, like B50 and above?

One mechanic recommended opening up the DPF after a few tanks and seeing if the filter was sooty, if it was clean, I was fine. Another has suggested installing an additional filter, a water filter, to further filter the biodiesel ... would you recommend that?

I was going to purchase my biodiesel from Yokayo Biofuels(www.ybiofueld.org), they make it from recycled cooking oil. I would really appreciate your thoughts. I dearly want to run this truck on biodiesel, and B99 if I can, but also need to not break an expensive machine!

Hi Jerome,

Thanks for writing. We understand your concern about biodiesel quality and applaud your cautious approach regarding its use in a very new and very expensive truck. Good move. So let's start by addressing your comments and questions one by one.

The Ford service manager is right about any peculiarities prohibiting biodiesel (BD) use in Ford's diesels. There really is nothing markedly different about their Powerstroke diesel that would make it less suitable for biodiesel than engines from other manufacturers (GM's Duramax or Chrysler's Cummins). They all use functionally-the-same basic components that just differ mainly in design.

The service manager however is not completely right about BD voiding the warranty. Check your owners manual carefully in the recommended fuels section and you'll find that Ford does permit the use of B5 (5 percent biodiesel blend). Where things can, and do, get tricky is when using more concentrated blends. While General Motors and Chrysler are very strongly considering allowing up to B20 blends, there are reasons for caution. The main concern that all the manufacturers have is the potential damage that improperly blended fuel (or high concentration BD) could do to the very delicate "clean diesel" emissions equipment on these sophisticated machines.

It's not really the engines themselves that are susceptible so much as the exhaust scrubbers. In particular, the Diesel Particulate Filter (DPF), Oxidation Catalyst (OxyCat), and (if equipped) Selective Catalytic Reduction (SCR) catalytic converter are extremely sensitive to contamination. A big concern with high concentrations of biodiesel is the alcohol content in the fuel itself. Most commercial BD is made with up to 20 percent methanol/ethanol which current diesel fuel/emissions system are not designed to accommodate. The most common problem encountered is a false "water in fuel" warning/error displayed by the engine management system. The high alcohol content of the BD fuel is misread as excessive oxygen (further misinterpreted as water) and usually sends a "check engine" warning along with the "water in fuel" warning.

We would agree that if you get your BD from a reputable distributor that carries only ASTM certified fuel, then the "poor quality fuel" issue would be much less onerous. Still though, a concern would be warranty. If you burn more than B5 and have a fuel related failure, Ford Motor Company would probably balk at covering the loss. And they easily could, and probably would, test the fuel remaining in the tank to determine its composition.

We're not so sure we'd agree with the "opening the DPF after a few tanks" advice to see what damage might be awaiting. These filters cost a bundle, and cracking the casing and exposing the soot-capturing-substrate probably would pretty much ruin it. We must admit, the "water filter," whatever that might be, sounds a bit iffy as well. Please remember that this truck, being only a 2008 model, is still under manufacturer warranty, and anything you do to the exhaust stack will almost certainly compromise that part of the warranty.

So, after all of this reasoning, here's what we recommend. Stay within Ford's guidelines (no more than B5) until the warranty expires. After that, feel free to experiment with higher concentrations of BD, but just small incremental increases at a time (say 5 percent). You'll probably be fine up to about B20, or maybe slightly more, but remember that these emissions systems are extremely finicky. You could be running fine for weeks upon weeks at a higher level of BD, and then bang, all of a sudden your (very expensive!!) DPF or OxyCat is clogged to the point of failure. Learn ... Experiment ... Push the envelope ... But be careful and smart. Good luck and feel free to write with more concerns and questions.

Christine and Scott

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