Tips for buying and using a car with biodiesel
February 8, 2007 9:58 PM   Subscribe

What car models are best for biodiesel? Anyone done the full conversion to vegetable oil?

Today my car died. Engine needs to be rebuilt so I am going to sell it for parts.

I'm going to buy something else and this time it's going to be able to run off biodiesel. Anyone have any experience with this and care to offer advice?

2002 or older is best for biodiesel I've heard. Any specific models good in particular? For biodiesel or just diesel in general. Mercedes? Volvo? VW?
posted by jruckman to Travel & Transportation (16 answers total) 1 user marked this as a favorite
There's some good info in this previous thread.
posted by vacapinta at 10:07 PM on February 8, 2007

One vote for a VW Golf TDI, here. The ability to mix with regular diesel is a useful crutch. 4 doors and a hatchback with a folding down back seat? So useful. ~40 mpg automatic. I would probably prefer a Jetta Wagon, but here in the Bay Area, they're basically the holy granola grail.

p.s. they sure are safe. We just bought our second after the first was knocked off the road and rolled twice down a thirty foot ravine by a drunk girl doing 105, listening to gnarls barkley and eating starburst in a rental car. Many airbags deployed and we walked away ok.
posted by Ambrosia Voyeur at 10:36 PM on February 8, 2007

posted by Ambrosia Voyeur at 10:37 PM on February 8, 2007

Response by poster: Ambrosia Voyeur: "the holy granola grail" LOL
posted by jruckman at 3:13 AM on February 9, 2007

I'd get an early 1980s mercedes 300d - I love those cars, and I have heard nothing but good things about any biodiesel/full veggie conversions on them.
posted by sluggo at 3:49 AM on February 9, 2007

My wife did TONS of research on this before settling on her Volkswagen Jetta TDI. I'll get details from her and update you on the 'why' behind her decision... It's a manual shift, btw, and she loves it.
posted by richmondparker at 5:20 AM on February 9, 2007

Seconding sluggo - my brother occasionally runs biodiesel in his 1982 300D with no problem, and that car is a tank. Built like a brick shithouse and easy to maintain. Comfy too.
posted by djb at 5:35 AM on February 9, 2007

A guy in my church did it with a diesel VW Bug. He gets his oil from a burger joint.
posted by 4ster at 6:31 AM on February 9, 2007

My father in law converted two early 80s Mercedes diesels to run off a second tank with vegetable oil. There's a lot of stuff having to do with filtration and switching. He's currently writing a book about it.

He doesn't do biodiesel, though.
posted by mkb at 6:34 AM on February 9, 2007

TDI VW bug owner here! My city has a biodiesel filling station. That helps quite a bit. I don't wanna do my own french fry stuff!
posted by k8t at 7:42 AM on February 9, 2007

There's a company called LiquidSolar in Ithaca, NY that does Biodiesel/veggie oil conversions. The last couple of years I was at Cornell, I saw one of their biodiesel Jettas quite frequently, and they did a conversion of a big Dodge (I think, might've been GMC?) diesel van for a campus environmental group I was involved in. I don't know anything about their prices, though.
posted by Alterscape at 8:04 AM on February 9, 2007

Pretty much any diesel engine can be run on biodiesel, but there are a couple of things to consider. Cars built before 1994 or so often have fuel lines that contain natural rubber, which is rotted quickly by biodiesel, but if your 15-year-old car still has its original fuel lines it's time for you to replace them anyway. On the other end of the age spectrum, auto manufacturers have been very cautious about embracing biodiesel. VW, for example, recommends diesel blended with no greater than 20% biodiesel for use in its cars. There have been stories about VW declining warranty coverage on engine repairs due to use of "unapproved fuels". (The solution for B100 users who need warranty coverage seems to be as simple as filling up with diesel before bringing the car in, but having a car covered with "Biodiesel - Fuel for the Revolution" stickers probably doesn't help.)

If you're running vegetable oil (not chemically converted to biodiesel), then your choices of suitable engines become smaller. A few examples: older Mercedes work well, but the particulate traps in the new Bluetec engines are rumored to cause problems. If you're looking at trucks, the Cummins 1993.5 - 1998.5 12-valve Dodges are good, but VO will be the kiss of death for the 1998+ 24-valve ones. VWs made before the 2003.5 models (when they switched to the "Pumpe Duese" unit injectors) seem to work fine on vegetable oil, but the newer ones are more of a gamble. The bottom line is, do some research into not just the model but also the specific year of the engine before you buy.

Unlike biodiesel, veg oil requires engine modifications that are not easy to hide, and will almost certainly void your engine's warranty. It's only been in the past 6 or 7 years that VO has moved beyond the patchouli-scented hobbyist market, and during that time the technology and the best practices have evolved tremendously. No doubt they will continue to evolve, so this is not a mature technology by any means.

That being said, I have a 2001 Jetta with an Elsbett single-tank conversion -- my brother-in-law has a 1999 Beetle with a Greasecar conversion. (And yes, Ambrosia Voyeur, I am another Bay Area resident in search of the Holy Granola Grail. See you on craigslist!) Both have tens of thousands of miles on them with no fuel-related problems. I get my oil from a local Japanese restaurant, and he gets his from the restaurant he owns (so it saves him both the cost of the fuel and the cost of disposing of the waste oil.) Feel free to email if you have more questions (it's in my profile) -- I could talk about this stuff all day.
posted by harkin banks at 8:50 AM on February 9, 2007

As harkin banks says, any (modern) diesel engine can run ASTM D 6751 conformant biodiesel (all commercially available ones will be). The oil and automotive companies have worked very hard to be sure that this is so.

Unless you have a special supply, running pure biodiesel is going to difficult from regular filling stations. Most US diesels in the next year are going to be B2 to B3 (Canada is aiming for B5 but I don't know if we'll get there). B20 is also available, but at higher cost.

You can certainly make biodiesel yourself. The risk to your engine is that home-made fuel is frequently contaminated with glycerine and/or solids. This causes a varnish-like build-up in the engine. Ignition may also not be as good (timing off, etc...).

Finally, biodiesel, unlike petrodiesel does go off. Bacteria and fungi love it, and will even degrade it anaerobically. They need water though, so try to keep stored fuel as dry as possible. An ASTM standard fuel should last for three months at least though.
posted by bonehead at 9:25 AM on February 9, 2007

My favorite pizza joint here in Madison converted 4 of their delivery vehicles to BD. In the article about it, they show pictures of one mini-pickup and one VW.
posted by thanotopsis at 11:20 AM on February 9, 2007

Yeah, thanotopsis, I saw the Nickel's VW pickup the other day. Very cool (pretty good pizza, too!).
posted by altcountryman at 3:32 PM on February 9, 2007

Response by poster: Right on, thanks for the comments. There's a co-op starting up in my area which will be producing and distributing fuel, so I'm looking to get a head start.
posted by jruckman at 9:17 PM on February 9, 2007

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