What is the best way to clean a fuel tank without cutting it open?

and if I were to cut it open, DIY style, what precautions should I have after emptying out all the gasoline and cutting the sides?

I was thinking to either flush it completely full with water, jiggle as much of that around and then throw a match inside for any excess gas still there to prevent some sort of detonation from the spark of the metal cutter.

and also, would sandpaper or just a metal scrubber be good for inside the fuel tank, should I paint it to prevent further rust residue from flaking off after I clean it?

My friend has his set of opinions, including acetone and gravel (which sounds like there's a chance a piece gravel will stay inside the tank...) but I do want as many opinions before I finally settle on an idea.

 

Use Ethanol and a power washer. Power wash it out first with soapy water, purple power etc. Soak it for a good 24 hours in ethanol and then power was again. You can probably fit a toilet brush or something up through the hole to scrub. After it is dry spray a liberal amount of WD-40 inside.

 

What about the acid bath and tank sealant I keep reading about?

 

I've used this kit twice (first on an Audi 4000, 2nd time on my 240Z):

POR-15 Fuel Tank Repair Kit

Had great results both times. The only thing to really make sure of is that the feed, return and vent lines are clear when sealing, but pipe cleaners stuck down each line takes care of that.

 

I've heard really good things about the POR15 fuel tank kit aye. Haven't used it myself... Yet!

 

ethanol I wonder if you mean something like this <CLICK ME> www.zoro.com

you think just putting in a gallon of fuel and shaking that around should be as good as WD-40?

I only prefer putting pre-mix oil (like mystery marvel) into the fuel tank instead of WD-40.



POR15 treatment seems a tad bit MUCH at $86 without a guarantee of cleaning it.

How old was the audi and 240 (also SX or Z, the Z seems more notorious for builidng up rust)

 

Well you get what you pay for, IMO. After $86 and the POR-15 treatment, both tanks were spotless and perfectly sealed inside. If you follow the steps to a T, it'll work. At least, it did for me.

The Audi was an '86 and the 240Z is a '72 and had been sitting with a few gallons of bad gas in the tank for ~8 years.

 

Ethanol from a fuel station. E85. Put a couple gallons in a lawn mower tank and use it to clean. Best degreaser Ever. WD-40 is easy to spray and is for rust prevention.

 

Took mine out, then off to the Rad shop for a chem dunk and cleaning. Then POR-15 Tank Kit to "line" the tank inside (essentially: seal it). Better than new.

You're not trying to degrease the tank - you want the flakey scunge that WAS the tank's innards outta there. Then you want to protect the newly exposed tank sides from it all happening again. Not sure what the various oil-type additives some suggest would do. A lube won't remove the flakey stuff, and the first tank of gas will dissolve the lube so... wouldn't you be back where you started?

Stu Aull
80GS
Alaska

 

Fill er up with white vinegar and add some baking soda. Sit overnight then clean. The heat it generates really helps. Saw it on a tv show.

Or just take it to a radiator or tank shop and have them hot tank and reseal it for you but ain't cheep.

 

Which method is best depends on what the interior looks like. I recently cleaned an FD tank that had been sitting with old gas in it for 10 years. At first the interior looked terrible, with this awful-smelling varnish-like goo everywhere. I used gasoline (with 10% ethanol) and swished it around / drained it numerous times, then acetone. By the time I was done, the interior looked almost new.

If the interior isn't rusty, just coated with sludge, this method may work for you, with the added benefit that you don't remove the galvanized coating, so you don't need to coat it afterwards.