Cleaning Fuel Tank

[Boatguy30]

Any good ideas to clean the plaque build up from the inside of an aluminum alloy diesel tank. I have the tank out of the boat so I can shake/ invert as needed. It seems the gunk is pretty well stuck on the bottom especially of the tanks. Have only a small amount of access from the top thru the fill and the guage hole.
Cheers,
Jeff

[DeepFrz]

Now is a great time to cut access holes so you can get access to each of the chambers. Then a piece of plastic like a credit card can be used to scrape off the tar and crud. You will want to carefully inspect the tank after because it may be badly pitted under the gunk. Good luck.

Before you install it (or a new tank) its also a good opportunity to install pickup and return tubing for a fuel polishing system.

[beneteau-500]

well having had my tanks empty for the past 5 months and i have no real inspection openings only that of the fuel guage i was recomened to use some stuff called starbright star tron cleaner my tanks hold 250 liters each so i filled one tank and added a litre of the starbright and fitted a tempory 12 volt pump with a spare racor 10 micron filter and pumped back and forth between tanks and four filters later at 16 euros each the fuel and tanks are clean

[Chief Engineer]

I don't believe you....sorry.....how did you see past the baffles in the tanks?

[r.furborough]

I have to agree with Chief on this, I cleaned my tank out last year and the crud sticks to the side of the tank like *****, it has to be scraped off. My tank does not have baffles but had an inspection plug that was just big enough to get my arm in. I cannot see any way any solvent could clean a tank properly without mechanical agitation or scraping.

[FreeSC]

OK...Ii HAVE THE EASY ...CHEAP ANSWER....

i HAVE DONE THIS FOR 3 OF MY BOATS AND 4 OF MY NIEGHBORS BOATS... IF THE TANK IS REMOVED.. AND ALuminum...

first hose it out as best as possible...then... go to a
HVAC supply store.. and get a gallon of "foaming coil cleaner" (a strong base)... it is an alluminum cleaner... pour half of the gallon in..add 3 or 4 gallons of water...let it sit 10 minutes a side...rotating the tank to every side..botom and alll 4 sides... it will foam all the gunk out of the holes..... dump it... rinse well repeat,,, then let the tank sit in the hot sun to dry out several days... the inside of the tank will be clean and shiny like new! total cost ..about $15.. and a few hours time!

the last one i did had 1" off algea in the bottom before i started...

the owner had a new engine to install ..so we also replaced all the fuel lines and filters and cleaned the filter housings...

good luck

[FreeSC]

Also...i usually have an electric fuel pump and 2 racor filters inline the first one a 30 micron element and the second a 2 micron element... most engines have a small filter ..but consider that a "filter of last resort"... remember diesels are very reliable, most problems with them are fuel contamination.. also replace your fuel deck fitting O'rings and have a spare or 2 aboard.. the algea in diesel thrives from moisture..you can't do much about condesation but you can stop the leaks from water though the deck fitting!

[beneteau-500]

cheif eng we used an endoscope to go through the bottom of the baffles and have also done fuel samples as well i was not going to chance ruining my engine after a $3500 engine rebuild

[Chief Engineer]

Was that one of those video models?

I am thinking aboot getting one.

How long was the probe?

Does it have a light on the end?

[chuck711]

I've found by the time you cut an access port in a aluminum tank,
make a proper cover /gasket and Tap 14 or so holes
you could buy and install a new tank.

Typically after you scrape the crud off the bottom a leak develops!!

[Boatguy30]

Thanks for all the replies. Not so sure about the guy who didn't believe me??? The tank was only 18 gallons and no baffles. I ended up cleaning it out with boiling vinegar and a putty knife attached to a stick. I did uncover one small pitting spot which was surprising for a freshwater boat. Not too bad yet so I fiberglassed a small patch on the outside under the tank. Will probably replace in a few years with a somewhat larger poly tank if I keep the boat.

Cheers,
Jeff