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Hedgehog's avatar
Hedgehog
Explorer
Jun 20, 2013

Possible algae is fuel tank

My diesel motor home has been sitting since October with a full tank of fuel. A month ago, I put around 200 miles on it with no problems. Well after talking to a friend of mine that just had to change the fuel filters 2 times just to make a 200 mile trip, I drained some fuel from my filters and found what looked like several brownish black snots in the fuel. Other than that, the fuel looks clean. I am going out to purchase a bottle of power service bio kleen as soon as the store opens but I'm wondering if I should start treatment now or wait until I come back from camping.i do carry a spare set of fuel filters but I'm leaving today for a 400 mile trip. Should I put the treatment in now or wait until I come home? Like I said, the coach is running fine, I just want to nip this problem in the bud. Any input is appreciated.

10 Replies

  • Hedgehog, the brownish/black "snot" in your diesel is a classic description of microbes/bacteria growing in your diesel. "Algae" may not be the technically correct word to use, but to the nonprofessional it makes no difference what word we use to describe it. As the T-shirt says, $hit happens!

    Good for you finding it early! It tends to get worse with time, and there have been cases that a lot of damage and expense results from such contamination. It can get to the point that changing filters won't be enough to compensate for the problems in a tank of bad diesel.

    I hate to say it, but the use of biodiesel fuel mixes may aggrevate the situation. Such fuels are noted to attract and hold water more than straight diesel, and do not have as long a shelf life. Unfortunately, our Federal tax dollars and in some cases state laws are promoting the use of biodiesel just like ethanol blends in the gasoline world.

    Such factors do not affect as much those folks who use up their diesel quickly, like long-haul truckers. We RVers (and boaters) are not so lucky as we tend to use our equipment less frequently, thus prolonging the amount of time we have diesel sitting there spoiling.

    Using additives in stored diesel is a good idea. If you suspect you may have some water in the diesel, a biocide such as BioBar JF will keep the microbes/bacteria from growing and is especially advantageous in high humidity climates.
  • Well, I treated the fuel with power service bio kleen and topped off on fuel. Just drove 200 miles and the engine didn't skip a beat. I have 3 sets of filters and 2 gallons of fuel for priming but hopefully I won't need them. I'll keep you guys posted. Thanks
  • The Texan wrote:
    Good reading......counters some statements.

    FAQ's about algae in diesel fuel


    I read it. It's wrong about fuel needing sunlight for algae to grow. Maybe they're not taking into account the contamination that can be accidentally added to the fuel or they're from a region where it just doesn't grow naturally. What ever the case, there's just too much evidence of algae growing in closed, dark bulk containers to ignore it. I've personally seen it and had it diagnosed by the bulk fuel supply company that provided the fuel.
    The OP would be better off calling a distributor in their area and asking questions.
  • Hedge,

    Biological activity in diesel fuel is a well known issue. Even if there is no water in the bottom of the tank, bugs can make some if they get the chance. When they get started they make more and grow more....

    It may look like rusty water, but I doubt very much that it is. Adding biocide is a good idea. There is no reason to wait either after treating or before.

    If you see evidence of this, then it is a good idea to care spares of all the fuel filters and know exactly what needs to happen if you get fuel bound. Knowing about your fuel system is something every owner should take the time to learn.

    Out on ships and boats this is much more important, but it is still a good idea standing on the dirt.

    Matt
  • Treat now and purchase 2 more sets of filters. I doubt you have algae, as that takes water and heat to grow in diesel fuel. It is probably just normal gunk that forms on the sides of diesel tanks and when it comes loose will look like you describe.

    If you have been traveling in Mexico and using LSD, then you will get those globs when you return to the US and switch back to ULSD.
  • I would shock treat the fuel and wait the required time before leaving on trip. Wait time should be 24 hours or less and should be stated on bottle.
  • Bacteria can grow in diesel fuel. Another thing, how could I tell if its bacteria or just little bits of rust?
  • i don't see how algae is possible in a fuel tank, unless there is a strain ???