Bio diesel

I have two diesel vehicles: a 2000 VW Jetta TDI and a 1987 Ford F250 pickup. To salve my conscience, I like to run bio diesel in these vehicles. In the winter (I live at 8200 ft in the Colorado Rockies), I usually run B20 (20% bio, 80% diesel), but in the summer I run 100% bio diesel in the Jetta.

I have two questions:

1. Do I need to worry about/replace the fuel lines? A mechanic replacing my truck battery scared me by claiming the oil, even in B20, will eat the rubber fuel lines, eventually clogging the fuel filter and/or causing a fuel leak.

2. I often have difficulty starting the Ford in the winter, and suspect the fuel is gelling. But I never have that problem with the Jetta. What can I do to make the Ford start more reliably in winter?

The ol’ IDI (in-direct injection) Ford motors are harder to start in the cold.

One thing that is a common trouble point in those motors are bad glow plugs. You can run some anti-gelling additive in your Ford’s fuel, but you would probably do well to have the entire glow plug system checked out. Or it could be a matter of needing your injector pump timed, or a failing lift pump, lots of different things. I’m not really an IDI expert, but here is a great site that has a forum that caters to that motor. I’d bet if you ask the same question over there, you will get lots of expert advice:

I’ve not heard of damage from correctly-prepared biodiesel, but I have heard that the fuel filters require more-frequent changing.

Stop by They have all the answers to all your questions and answers to all the questions you don’t know you should ask about.

I have a TDI but I don’t do bio so I am not up on the details. I believe VW recommends up to either 5 or 10% max, but many go over that with out problems. The current 2009 models are different and bio does not seem to work well with them.

B20 is diluted enough with regular diesel that it shouldn’t cause any problems. The straight bio-diesel might cause some rubber fuel hoses to deteriorate a little faster on the Jetta, so they should be periodically inspected, but it shouldn’t really cause serious problems. I probably wouldn’t use straight bio-diesel on the Ford just because of the age of the fuel components.

I will mention though, that back when I had an old 1980 Mercedes 240D I found I got significantly poorer mileage with B20. It wasn’t quite 20% less, but it was close so I figured I was probably in the greater scheme of things using less fossil fuels using the straight diesel. Also, I know this was a technical question and not a solicitation for a political harangue, but you might want to look into the total energy costs of bio-diesel. It’s not quite as bad as ethanol, but commercially produced bio-diesel still usually uses more energy during its production and refining than it yields. I think your conscience should be salved enough by simply burning less diesel with your very efficient TDI.

As for the Ford, given its age, it may just be losing compression. Good compression is essential for quick starting on a diesel and since you’re at such a high altitude your compression is naturally lower, so you’ve already got that working against you, and if the compression is getting even lower due to wear it’ll make it a lot harder to start. I’d suggest a compression test before you throw too much money into that problem.

Aside from the engine damage issues, you might want to know that biodiesel isn’t always a ‘green’ fuel. Thousands of acres of rain forests have been cut down in Indonesia to grow palm trees for biodiesel, an ecological disaster.

All new diesel engine manufacturers only recommend a B10 blend of bio-diesel. Prior to this, B5 was the max blend.