Fuel tank cleaning?

My project Fiat seems to have been stored for the better part of 2 decades with a half tank of gas in it. The fuel level sender was removed during this time so vapors had a nice easy path to escape from.

What I am left with is a very thick, gummy tar like substance about 3 inches thick on the bottom of the tank. I managed to scrape some out and tried different solvents on it. Acetone did nothing, the solvent from my parts washer had zero effect, naptha zilch. However regular old laquer thinner started to break it down pretty well.

I pulled the tank to start cleaning. I am three days into this. I pour a gallon of thinner in and start scraping through the sender hole, wait a day, scrape some more and pour it out, pour more in and wait and scrape. Very labor inte3nsive and I am starting to get nauseous from the fumes. It is working but the tank is baffled and I cannot get to the last half.

I am having no luck finding someone who will clean tanks locally, radiator shops say "we dont do gas tanks" and I REALLY dont want to cut access holes into a otherwise perfect and totally unobtainable tant.

Ideas?

Add some fresh gas, some marbles or similar, seal it up and shake the hell out of it, when its clear rinse with water, yes water, let it drain until dry and then repaint the outside, I used POR for this job.

This has worked for me several times but I have not had to deal with the baffles

Wow. You stymied me when you said the local radiator shops won't boil gas tanks, as that's where I took my Celica tank after it had sat for 18 years.

If you post up a location, someone who's local to you might be able to suggest somewhere to go. The place I went to is in Petaluma, CA.

A side thought I had: if the radiator shops won't dip your tank, they might be kind enough to tell you what chemicals they used when they did.

Dump 2 boxes of 1/4-3/8 nuts in the tank and a 1/2 gallon of acetone. Shake the crap out of it with a freind. Pour out goo... Add star washers if trying to remove rust.

44dwarf

I'd dump 3-4 gallons of lacquer thinner in the tank, seal off the holes leaving a small vent hole maybe 1/4" in diameter and let it sit for a week or two then empty it out. 44's nuts and star washer thing works well, I've done motorcycle tanks that way.

It's a good idea to seal the tank internally after cleaning it, but be careful! Lots of gasolines today have ethanol in them and the old standby tank sealers like 'Kreem' won't stand up to alcohol. That means the first time you fill the tank you get a huge blob of goo in the bottom of the tank. Bad news, particularly if it hardens.

I would keep looking for a radiator shop to take the job, doing the job at home is simply not worth the tax on your lungs/skin.

Good suggestions here but I'd replace the gasoline/acetone with lacquer thinner as a solvent since that seems to be the only thing that's working for you...but yeah , wear a gas mask and gloves if possible, ideally try and find a shop to do it, it's not good for your lungs, skin, eyes, and according to the warning labels, nervous system.

I'd do what you're doing to get the sludge out. Then, fill the thing up with Vinegar (available in gallon jugs at your local grocery store) and let it sit for a good long time (a week would probably do). Follow that up with a scrub brush and a throrough rinse and dry. Then spray it down with WD40 or the like.

Vinegar is a nice, mild acid that takes care of rust handily with time. You didn't say you had issues with rust, but given the fact that you had an open tank, half full of gas, I'd guess you might have some issues with rust.

I have learned, however, not to use vinegar on carburetors. It does nasty stuff to the aluminum!

Clem

I am going to call around again. the website of one the radiator shops I called says gas tank cleaning/restoration right in their list of services.

I cant take the stench anymore.

GameboyRMH wrote: Good suggestions here but I'd replace the gasoline/acetone with lacquer thinner as a solvent since that seems to be the only thing that's working for you...but yeah , wear a gas mask and gloves if possible, ideally try and find a shop to do it, it's not good for your lungs, skin, eyes, and according to the warning labels, nervous system.

[twitch] It hasn't affected [twitch] my nervous system [jerk] as far as I can [twitch] tell. I'm no more [rattle] nevous than I ever was. [twitch]

My father bought a 1948 Chevy truck that had been sitting for 20 years. He removed the tank and built a contraption so he could rotate the tank and dump it easily (he lives in the middle of nowhere, and we believe dumping a little stuff won't kill the world).

He did the lacquer thing, with nuts for agitation. Over and over, every day for a week.

Afterwards, he had to install a fuel filter (optional on this model), and clean it frequently.

We used to clean outboard engine tanks with lye.

I called around again. Crikey!! they charge by the baffle. $200-225 for an 8 gallon tank.

Back to scraping.

The nuts/bolts/marbles idea just wont work. this goo is thick and sticky like roofing patch tar.

I had to take up 30 year old mastic off the floor and used some jasco adhesive remover. Nasty stuff but it seemed to work. I think it was a mix of methyl alcohol and methylene chloride with a wax to stabilize it. Nasty stuff but it cleaned up a concrete floor. The only issue is that it is water rinse which may be a problem with a steel tank. The other thing you might try is to hit it with some brake cleaner. Good luck.

As with most nuisances in life, I'm pretty sure fire is the answer.

Set the tank on an old tire. Rig up a contraption with an old electric motor, a crank arm and a small weight. Strap it to the tank securely. Fill the tank 1/2 full with the best solvent and a bunch of nuts and bolts. Turn the motor on, which will make it vibrate in a rotary type fashion. Come back in a day and dump. Repeat until clean.

If the stuff is that thick and gooey, I'm not seeing any quick way to do it. Dave's 'constant agitation' idea is pretty good if you can rig it up.

poopshovel wrote: As with most nuisances in life, I'm pretty sure fire is the answer.

Funny you should mention that. I got a "Nuisance Notice" from the city regarding a vacant lot I own with some lumber and brush on it. Fire IS the answer!

I'm going to have a bonfire on the next evening with reasonable weather. Of course, that could be in March.

Clem

poopshovel wrote: As with most nuisances in life, I'm pretty sure fire is the answer.

Not sure if this was in jest or not but it turned out to be the right choice. I got it down to a 1/4 layer of sludge in the tank that would not budge. I experimented by heating the outside of the tank and it bubbled right off. So I lit the damn thing on fire. It burned at a pretty low temp for a few minutes, never even bubbled the exterior paint. Now I have a thin layer of crispy char and ash that I can scrape off with nuts and bolts/agitation.

Getting there!!

ditchdigger wrote:

poopshovel wrote: As with most nuisances in life, I'm pretty sure fire is the answer.

Not sure if this was in jest or not but it turned out to be the right choice. I got it down to a 1/4 layer of sludge in the tank that would not budge. I experimented by heating the outside of the tank and it bubbled right off. So I lit the damn thing on fire. It burned at a pretty low temp for a few minutes, never even bubbled the exterior paint. Now I have a thin layer of crispy char and ash that I can scrape off with nuts and bolts/agitation. Getting there!!

Wow. Glad you didn't go boom.

ditchdigger wrote: I am going to call around again. the website of one the radiator shops I called says gas tank cleaning/restoration right in their list of services. I cant take the stench anymore.

If they will do it, let em. I could not find one that would touch it.

I had good luck with Red Devil lye, hot water and roofing nails. Shake like crazy. Don't get the liquid on your skin.

DILYSI Dave wrote:

ditchdigger wrote:

poopshovel wrote: As with most nuisances in life, I'm pretty sure fire is the answer.

Not sure if this was in jest or not but it turned out to be the right choice. I got it down to a 1/4 layer of sludge in the tank that would not budge. I experimented by heating the outside of the tank and it bubbled right off. So I lit the damn thing on fire. It burned at a pretty low temp for a few minutes, never even bubbled the exterior paint. Now I have a thin layer of crispy char and ash that I can scrape off with nuts and bolts/agitation. Getting there!!

Wow. Glad you didn't go boom.

You are MUCH braver than me. Gasoline goo containing lacquer thinner is probably not a good thing to get real hot.

I did a test burn on some of the crap scraped out of there. It was suprisingly resistant to burn. Said screw it and lit it up. It tended to starve itself of oxygen and go out every 3 minutes or so.

Filled the tank with a couple pounds of 3/4" split lock washers and shook the hell out of it for a half an hour. It is looking pretty good in there now. Definatley useable.