Biodiesel Guide: 7 Steps to Buying a Diesel

biodieselcarThinking about ‘converting’ to biodiesel?

It’s not as hard as you think.

This series of posts is intended for readers looking to start using biodiesel by finding an older diesel vehicle, ‘converting it’, and then finding a local fuel source.

Before embarking on a biodiesel adventure, it may be a good idea to determine whether biodiesel is available in your area (it probably is), and most importantly, whether or not it’s conveniently located. While some of us are willing to go to great lengths to find and use alternatives to petroleum-based fuels, this isn’t practical for everyone.

For information on how to find biodiesel, see 6 Ways To Find And Use Biodiesel Anywhere, and for more background you may want to get started with the Biodiesel Mythbuster. This post is primarily focused on buying a used diesel, but it should be helpful to anyone interested in using biodiesel.

Finding Your First Biodiesel Car (or Truck)

It’s important to understand that any diesel engine can run on any blend of biodiesel with no major conversion. In older vehicles, it’s not a bad idea to change out fuel lines (biodiesel eats rubber over time), but don’t let anyone convince you that this is difficult or expensive (more on this later). First, let’s find your first biodiesel vehicle:

Step 1: Determine Your Needs

Will this be a commuter car or do you plan to live out of it for the summer?

This might seem like an obvious consideration, but make a sincere effort to use the same criteria you would for any vehicle purchase. Don’t let the excitement of buying a diesel cloud your judgment, and trust me, it will. Anyone on Ebay knows how easy it is to click the ‘Buy-it-Now’ button, and you may end up in a noisy tin can that won’t go over 55 mph.

Here are some things to consider:

  • Do-it-yourselfers should look for pre-1990 vehicles, since engine components get considerably more complicated with each passing year. Workspace also decreases dramatically as more parts are crammed under the hood. Changing out fuel lines in a 1982 Datsun is a snap. Accessing the same lines in a 1987 Toyota is considerably more difficult unless you have small hands and considerable dexterity.
  • Small Trucks are hard to find. If you want the versatility of a truck but don’t need to tow a super-tanker, you may have a hard time finding a reasonable compromise. Larger Ford models (F-250, F-350) and Dodge trucks are ubiquitous, but huge–not a good choice for the city. The only small-model trucks I’ve seen are Datsuns, VW Rabbits, and the oh-so-rare Toyota diesels.
  • Diesels are more expensive. Diesel engines last longer, so seeing 190K miles is not uncommon. Expect a diesel that’s running and in decent condition to set you back about $5,000. If you don’t pay $5,000 for a diesel, expect to put as much as $2,000 in maintenance costs into the beast in the first 2 years. You may get lucky, but you tend to get what you pay for.
  • Not all diesels get fantastic mileage, but most passenger cars do. Take a look at VW models like the Jetta, Golf, Beetle, and Passat. In most of these you can easily get 45+ mpg.
  • Make sure you can find parts for you new car. Finding a one-of-a-kind truck may not be so great when your injection pump fails.

Step 2: Start Looking

Some places to look:

Your best bet is to search Craigslist (free local classifieds) in your area under ‘cars+trucks’. The local newspaper and Autotrader are also options, but Craigslist seems to offer lower prices and less hassle. Search for ‘diesel’ and set the maximum price you’re willing to pay.

If you’re lucky, you can also find good deals on Ebay Motors. Just remember that everyone is on Ebay (as opposed to your local Craigslist), so it’s hard to get lucky. You also have to deal with long-distance buying, which introduces numerous complicating variables that you don’t necessarily want to deal with. I would recommend buying locally, defined as within an easy day’s drive from your current location.

Another good source may be the classified sections of online forums, such as ToyotaDieselMadness or the Nissan-Diesel Forum.

Step 3: Ask Questions

This is especially important for older diesels. When you see the car (or truck) of your dreams remember: it may be too good to be true. Not that the seller is a swindler, but it’s standard practice to gloss over the less-desirable features of your soon-to-be new car. Be aware that in many areas (like the Pacific NW), biodiesel-ready vehicles will fetch a tidy premium, and ‘runs great’ would be more accurately read as ‘it runs!’

Here are a few questions to be sure to ask:

What kind of mileage does it get?

Does it burn oil?

What major repairs have been done?

What needs to be done?

Have you run it on biodiesel?

If yes, have the fuel lines been changed yet?

When was the last fuel filter change?

Here are a few more ideas.

Step 4: Get the Vehicle Inspected

A good seller should have no problem taking the vehicle to a mechanic for routine inspection. This shouldn’t cost more than about $80—unless you run into problems—and is absolutely worth the money. Ask to speak directly to the mechanic, and don’t let them off easy. If the mechanic says “It’s fine, except for such and such,” ask them what the specific problem is and how much it will cost to fix. Remember: $200 now, even if you decide not to buy the car, is much better than $2000 later. Beware of sellers who balk at the proposition since they may be hiding something.

August, 2007: “It runs great, except it’s really low power.” This was coming from a mechanic in Bozeman, MT, advising me on the purchase of a 1987 Toyota diesel truck. What I would learn 3 weeks after buying the vehicle and driving it back to Oregon was that the injection pump was due for a ‘catastrophic failure’. Oops. Price tag for this mistake: $720 and counting. Moral of the story: don’t take their word for it…

Since we’re talking about diesel engines, you may also consider getting a compression test done to test the health of the engine before you commit to any financial hardship.

Step 5: Inspect the Vehicle Yourself

You don’t have to know anything about cars to do this. Look underneath the car and check for leaks. Check the body for rust and signs of repair. Check the tires for uneven wear. Does the engine look clean and tidy, or does it look like the vehicle spent the last 6 months in Afghanistan (I actually had a mechanic say that about my engine once). Ask about anything that looks abnormal.

Step 6: Take a Test Drive

This step is all-important. New cars require a more refined set of criteria (e.g. do I really need leather seats?), but with old diesels the major deal-breaking issues must be carefully evaluated. Besides the car actually running, you should consider:

  • Noise
  • Driveability

Noise. I bet you never thought about this one but, trust me, older diesels can be extremely loud. Make sure you get on the freeway and push the vehicle to max operating speed (probably 65-70 mph). Could you have a conversation in the cab, or would you have to shout? Think you could stand 10 hours in there without a headache or ringing ears?

Driveability. How comfortable is the vehicle to drive? Does it ride smoothly and stop straight? How are the seats? Does it shimmy when it hits a bump? Make sure the dash lights, blinkers, and speedometer work.

Step 7: Final Evaluation Criteria

Having a ‘good feeling’ isn’t enough, and should be tempered with careful evaluation of the vehicle’s overall condition and the cost of fixing any apparent problems. That being said, make sure you like (or at least can tolerate) the car or truck you buy, since that goes a long way for having the patience to deal with future problems.

It also never hurts to get a second opinion before you buy. Is your significant other really going to let you park that in the driveway?

Next Stop:

Biodiesel Mythbuster 2.0: Twenty-Two Biodiesel Myths Dispelled

6 Ways To Find And Use Biodiesel Anywhere (Part I) and (Part II)

Learn How To Make Biodiesel On YouTube

Study: Buying Biodiesel May Be A Gamble

Photo Credit


In a past life, Clayton was a professional blogger and editor of Gas 2.0, Important Media’s blog covering the future of sustainable transportation. He was also the Managing Editor for GO Media, the predecessor to Important Media.