external tank cleaning

[jjriggins]

hi everyone..
my husband bought an external fuel tank for our truck because we are now full time rver's. he didn't check it out first and we found out after he bought it that the guy made his own fuel and that there is sludge in the bottom of the tank.. we can't fill it with gas until he cleans it but we don't know how to do that or what to use to dissolve this mess. he spent $300 in the 100 gallon tank so I really need him to clean . any one know what to do please help me!!!!

[theholycow]

What kind of tank is it? What kind of access do you have to its insides? Can it be cleaned with a brush or rag on a rod?

What kind of fuel was in it and what is the sludge? Was he making biodiesel out of waste vegetable oil?

I imagine gasoline or mineral spirits (paint thinner) would dissolve the sludge. Then you need a reasonable way to dispose of that...

[jjriggins]

well the man said he made bio fuel out of old veggie oil and the sludge is thick on the bottom. he has tried to pump it out but the sludge keeps clogging the pump.
that's why I asked if there was anything that would desolve it. the tank is an L shaped tank that sits in the bed of the truck with a toolbox in the L shape. we want to be able to travel without worring about not being near a fuel sorce .

[bobc455]

Wow, sounds like you got a really raw deal there.

You *might* try a radiator shop.

Or you might go to your local DIY car wash and spray soapy gunk up in there with their power washer nozzle.

-Bob C.

[trollbait]

Can you scrape some out with a stick or something? Then can test that out on different solvents on the scrapings. If it was biodiesel in there, it is possible the gunk, or part of it, is glycerine. That's water soluble. So try soapy water first, and it should also work with gunked up cooking oil.

If the water and soap works, I'd go with Bob's suggestion of the DIY car wash bay to get out most it, because that should have an oil seperator for the waste water so the gunk doesn't end up in the water supply.

If need to use another solvent, there is also kerosene, acetone(might remove paint on the tank) and rubbing or denatured alcohol to try in addition to the gasoline and mineral spirits. You might have to pay to dispose of the used solvent. With alcohol, you could let the alcohol evaporate off, leaving less to dispose of.

I think the water will work though. Followed up with some gasoline to get left over traces. The gunk should be a small enough amount to be able to use that gasoline in the lawnmower. Just add fuel injector cleaner(or mineral spirits or 91% rubbing alcohol) to it to ensure the dirt gets to the cylinder and burns.

Add Iso-Heet or the 91% rubbing alcohol to the first tankful of fuel in case some water is left.