algae [crud] in fuel tank - PeachParts Mercedes-Benz Forum

bng · #1 05-03-2008, 12:20 AM

veh 85 td 185k pri filter changed often as it gets restricted with black crud. ive tried additives but had little if any success. last prob was severe enuogh that it was necc to blow back thru line as tank strainer if equipped with or line was plugged to the point that elec lift pump couldnt pull fuel. this has been a prob in tropical climates [so fl] for a long time.does anyone know of a solution [chemical] rather then making tank removal part of maint. procedure. many thanks for responses regards butch

t walgamuth · #2 05-03-2008, 12:27 AM

YOu have bacteria growing, apparently, in your tank. It happens when there is water in the fuel either in your tank or someplace you buy fuel.

The solution is a treatment or so with biocide. It is available at truck tractor or marine stores.

Put in the biocide....it will kill the bacteria and then it will go through your filters harmlessly and be gone.

Good luck.

Tom W

Cervan · #3 05-03-2008, 02:45 AM

bleach, thatl kill it real quick

t walgamuth · #4 05-03-2008, 08:26 AM

ARe you kidding?

Thats not anything I would want to put in my tank.

Tom W

Brian Carlton · #5 05-03-2008, 09:24 AM

In addition to the biocide, plan on pulling and replacing the tank strainer. It's going to be covered in fungus.

chasinthesun · #6 05-03-2008, 11:08 AM

Pull the tank ,if its that severe it will need to be cleaned out ,radiator shops can boil it and clean the crude ,clean all your lines or replace with nice viton ones ,reinstall ,then you know your done with the stuff.If you let a car sit for more than 2 months I would add a gallon of diesel treated with the biocide every so often and run it for that gallon just to be safe.

doxland · #7 05-04-2008, 11:19 PM

In my experience, the dead bacteria/algae will not pass harmlessly. They will block the filters several times if it's a good infection. You'll know if you are getting results; The dead material smells pretty bad.

t walgamuth · #8 05-05-2008, 02:42 AM

I have had the problem several times and have never pulled the tank or strainer. The biocide has done the trick for me.

Tom W

pmari · #9 05-05-2008, 08:06 PM

To be accurate, the bacteria are small enough to go through the filters in our cars. The clogging problem arises from the biofilm that the bacteria secrete. The biofilm (slime) is what allows the critters to interface with their hydrocarbon based meal. This boundry layer is between the water and the fuel. This is why it is very important to be vigilant about activly ridding your fuel of water. Even if you get pristine fuel, condensation happens and over time there could be a problem. Startron contains an enzyme that lyses the biofilm, but if it is not used correctly, it won't work.

Quote:

Originally Posted by doxland

In my experience, the dead bacteria/algae will not pass harmlessly. They will block the filters several times if it's a good infection. You'll know if you are getting results; The dead material smells pretty bad.

runnysucklehose · #10 05-05-2008, 09:06 PM

He said the car is an '85 TD, so it's a wagon, right?

If it is a wagon, and it is anything like an '84 300TD, then the tank is super easy to drain.

If you have more than about 5 gallons of fuel in the tank try pumping most of it out through the filler hole.

Back the rear wheels up on ramps or jack it up, be sure to use jack stands.

Find a container large enough to hold the contents of the tank, you may want to have a backup with in easy reach.

The fuel strainer on the wagon does not have a hose attached to it like the D and SD, it is just a 46mm low prophile bolt in the middle of the bottom of the fuel tank (I got a 1-13/16th" socket from tractor supply for cheap) or you may be able to get it with channel locks or a big adjustable wrench. It is much easier to get at than on the sedans.

Be careful as you unscrew it.

Let the tank drain. Now is a good time to replace those old fuel lines under the car with some good Viton or other synthetic rubber hose.

Clean the tank strainer or replace it. Check that gasket it may be history. A new strainer should only cost about $20.

Reinstall the strainer.

Refill the tank with clean fuel and a good algea killer (you can get that stuff from marinas and heavyduty truck supply houses)

I would unhook the reutrn line and use the hand pump to pump clean fuel into the lines, collecting the old stuff in a coffee can or something.

Change the filters.

Reprime the system and you are off and running.

Keep using the algea killer or use a percentage of biodiesel, or both, and keep an extra filter or two in the car with you.

Hope that helps, lemme know if I need to explain something better.

As for the old fuel...You may be able to pour it through a coffee filter or two, or maybe cheese cloth, just be sure and use that algea killer if you do put it back. I have a 5 gallon container full of algeafied fuel that I am afraid to do anything with, even though I have a centrifuge oil filter that would take out the particles, I just don't want another contamination problem.

Joe

t walgamuth · #11 05-05-2008, 09:36 PM

Sure a tank is easy to drain, if you don't mind taking a bath in smelly Diesel fuel. Then what to do with it? The last time I drained a tank I had a Hellova time getting rid of it.

Try the biocide first. It usually works.

Tom W

JWJ · #12 05-05-2008, 11:40 PM

I've used biocide for both of my MBs when problems developed. After a few weeks of biocide use I removed the tank strainers and there was nothing left to clean off.

Removing the tank seems over the top to me.

bill murrow · #13 05-06-2008, 07:21 AM

had this problem myself. Star Tron, as mentioned, available from West Marine did the trick. It eats the bugs up allowing them to pass instead of clogging the filters like regular biocide.

Problem two was I still had a clogged tank strainer. Could not get it to budge to clean it so I simply switched the return and feed lines under the hood. At first I wondered if the return line [now the feed] went all the way to the bottom of the tank and it seems to so thats not an issue. I'm sure this fix isn't as good as removing the tank and cleaning it but it's been 2 years and I haven't had any problems.

pmari · #14 05-06-2008, 08:04 AM

Biodiesel will feed HUM bugs, just like Diesel

. Plus if you run a blend greater than B20, there is a chance of cleaning off old encrusted fuel varnish from the tanks walls. If that happens, you will need extra filters.

As suggested, it comes down to 2 methods. One is simple, pour in a biocide and I would suggest a dispersant also along with startron/xbee as directed for a couple bottles.
The second involves turning wrenches.

Quote:

Originally Posted by runnysucklehose

Keep using the algea killer or use a percentage of biodiesel, or both, and keep an extra filter or two in the car with you.
Joe

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