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Maintaining Your Biodiesel & Diesel Vehicle


Mercedes Benz BLUETEC

Check out this trio of diesel burning Benzes. Regular maintenance will keep them running like a charm.

photo © Mercedes-Benz

Regarding regular maintenance and repair, biodiesel vehicles are very similar to conventional vehicles—they are basically standard diesel engine vehicles that can burn biodiesel fuel. In fact, biodiesel vehicles are next in line after flex-fuel vehicles (FFVs) regarding their similarity to conventional gasoline-powered cars. However, these cars do have a few more potential maintenance “gotchas” to watch out for:

Watch out for Algae

Algae growth in the fuel tank and lines is a potential problem. Indeed, it may seem odd at first—how can anything grow and live in diesel fuel—but it is true, especially in warm and humid climates. And algae can live in petro diesel as well as biodiesel.

Algae, which looks like a dark green to black slime, may grow and thrive in the fuel tank and lines. It can be swept along with the fuel as it travels through the system, eventually getting trapped by the filter. As it grows and accumulates over the long haul, the algae can clog the fuel filter and prevent fuel flow.
    To Avoid Algae Problems:

  • Top Off Your Tank. Keep your fuel level topped off to prevent moisture build-up from condensation in the tank.

  • Use Algicides. Added to the fuel to control algae build-up, algicides are vital in hot, humid climates.

  • Change that Filter Regularly. Algae will grow in minute concentrations no matter the climate conditions—so keep the fuel filter changed on a regular basis, and it’ll never have a chance to clog.


Sludge tends to be a problem that is mostly limited to older diesels that have accumulated years and miles. It’s a “blackish” substance similar to algae—though it’s not living. Sludge builds up in the fuel system over time. Basically, it’s “dirt” that settles to the bottom of the fuel tank. While it is generally harmless settled at the bottom of the fuel tank, when biodiesel is added to the mix, the sludge can be loosened and suspended in the fuel, causing the fuel filter to clog more quickly.

Is biodiesel the bad guy here? Not really, actually it’s a good thing—biodiesel acts as a detergent and will eventually clean out most of the sludge that has built up in the fuel system.

    To Avoid Sludge problems:

  • Regular Fuel Filter Changes. When first switching to biodiesel in older vehicles, it may be necessary to change the fuel filter more frequently to remove the purged sludge.

  • If you suspect your very old vehicle has severe sludge build-up—say you’ve changed out several filters and they’re continuing to clog, you may want to consider having the fuel tank removed and pressure cleaned by a shop.

Cold Weather Concerns

See the following articles for the low-down on winter weather to keep your alternative fuel vehicle running its best when the cold winds blow:

Related Video
Winter Driving and Car Maintenance Tips

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