I've tried having my tank cleaned out at a radiator shop. I sloshed around a gallon of parts cleaner in it too. I still get varnish clogs in the fuel petcock after driving a few miles. The tank is not rusty inside, and I don't want to acid wash it, which would ruin the zinc plating inside. I think the baffles inside the tank made it hard for the radiator shop to do a good job.
Someone told me that acetone would work. The tank sat with old gas in it for about 8 years. I have another one in a similar condition too. Anyone out there have some advice?

I have a similar problem with my Model A and bought a can of acetone to try it out.

I recently had a problem with gummy gas residue clogging up a Dodge gastank, the only way I got it clean was to use brake parts cleaner because it had a large access hole where the sender went. The cheap stuff in the blue can from Walmart worked better than the expensive stuff from NAPA.

The old gas seems to turn gummy and clog things up, the new gas will rust out a tank in short order, almost acting like acid.

I would send the gas tank out to someone who cleans them (Radiator shop) . Its not worth trying something like that yourself. Its flammable you know?

The radiator shop tried, and failed me. I think they tried to use a pressure washer with hot soapy water. It might work on some tanks, but the Model T tank baffles are so close to the bottom, that they could not get beyond the first baffle.
I just solved my Model T problem with a new tank from Snyders. Too bad I can't do the same for my 1928 Gardner. I might look into Tank Renu.

I found a great way to clean my gas tank. Buy about 50 used golf balls. Go to Costco and buy 2 gals. Oil-Eater Cleaner Degreaser.
Mix 2 gals. Oil-Eater with 3 gals. water.

Make a cage out of a few 2x4 and plywood ends with center pivot so the tank can turn over freely inside it. Get a BBQ motor, stick in small shaft. Buy one of those big huge rubber bands or a piece of 5/8 heater hose with a nipple to connect both ends and have it go around the tank and the BBQ motor. Put the Oil-Eater mix and golf balls in the tank and block all open areas. Turn on motor and let run a few hours ( 3 to 4 a day for 2 or 3 days on off). Wash tank with clean water, rinse with baking soda ...Shazam! The rest I left out, just use common sense.

Golf balls won't work in the model T tank. There is less than 1/2" gap under the tank baffles, so no balls will roll under. No pressure washer nozzle will fit either. You need a good solvent, or a new tank.

A friend of mine who worked on Model Ts all of the time used 3/4 minus pea gravel and solvent to clean out numerous REALLY gunky T tanks. A whole lot of sloshing was involved, but it did the trick every time.

Buy Carburater cleaner ,The kind comes in 5 gallon for submurging carburaters. Its different than the spry cans.Use marbels they get into corners & by baffels.Put a filter before the fuel pump if possible.MEK is a good cleaner.Try Mills or Blaines might te cheapest.Are you sure its not in the lines????? Hope it helps. THERE IS A RADIATOR SHOP IN KENOSHA {UPTOWN RADIATOR 262-658-149} Call and see what equipment he has.

MEK (methyl ethyl ketone) from a paint store may cut it. Cost was $12.50/gal a couple years ago, cost now, ??. Pour it in, let it sit a while, slosh, strain it while draining, then pour it back through, sit, slosh, drain, strain, and so on, multiple times. Good luck. Dave

I try to use the KISS method wherever possible.

One can of Drano drain cleaner crystals (very cheap), two gallons of hot water, 1/2 gallon of pea gravel... seal all openings and do the twist with your tank until you get really tired. (Good exercise)

Strain & rinse the pea gravel & clean all the drains in your shop. (Always good to get two chores done at one time)

Rinse thouroughly and let dry in the sun...

This worked great on my 29 Buick tank many years ago. I do like the BBQ Rotisserie idea though...

I occasionally restore vintage motorcycle gas tanks and stumbled onto this, rather “unconventional” cleaning process a few years ago.

I’d take the gas tanks to a sandblaster and have them media-blast the exteriors. Then I’d repair the metal, clean out the insides, and return them later for the seal coating.
After they blasted a few tanks they suggested, ”burning” the tanks, which would save me time by cleaning the inside and the outside at the same time.
I thought they were testing my sense of humor, but they looked too serious to be joking and said: “We do it all the time. As long as it's aged gas and there aren’t any strong petroleum fumes, or liquids, we’ll burn the tanks in a “bake oven”.

The “bake oven” is like a powder-coating oven, but has a temp range of 600-800+ degrees. Heavily undercoated parts or calcified parts are burned for 6-8 hours, prior to blasting, which saves blasting time and is less damaging to the metal.

They have burned 30+ tanks (without incident). The tanks return varnish free on the inside, and are paint/ filler free on the outside.

To burn/blast a 2-gallon to 6-gallon cycle tank cost less than $40.00. To clean the interiors, I too bought degreasers, solvents etc. and spent the better part of 2 days sloshing, rinsing and drying. I consider the $40.00 cheap to clean the entire tank.

John, I’m unsure if the high heat would have adverse affects on zinc plating, and seal coating is recommended after burning, so I'm not sure if this is right for you. But, when burning, the baffles and irregular contours of a tank pose no problems.

(I'm not too familiar with all the Fords, so you guys with the built-in gas tanks, stick with the acetone, or carb cleaners. OK? )

Call some of the larger commercial blasting shops and get their advice. Had the shop I use not suggested it, I’d have never considered burning a gas tank! Ever!

Hope this helps!

My radiator shop cleaned a 30-gallon tank for me that had 40-plus years of varnish and rust inside. They completely filled it with caustic soda and let it sit. When I got it back it was pristine.

Is it plain steel inside, or was it coated? After the caustic soda treatment, it seems you would be prone to rusting easily.

Whether you wear-away or chemically etch, your zinc will be gone. You can do golf balls, Draino, stones, chains, heat, or 1/4-20 nuts (with or without caustic soda or methyl ethyl ketone). They all seem to do the job when done right. I sympathize with you because I too had this problem. As with your Model T, I bought a new tank and all my problems were over.
What about this? My tank contains a pickup tube with a screen on the end. Even though it's in the tank, it is very much a part of the fuel lines. You must clean the lines as well, because Gasohol (10%) will also disolve varnish and send it to your carb. For awhile, put a few BIG fuel filters in parallel, before your fuel pump. It helps to get the kind you can see through. When putting a few filters in parallel, the flow resistance goes down (it gets easier), and filtration capacity goes up.

Regarding the caustic soda treatment, after I got the tank back I then used a commercial cleaning solvent, then an etching solution, and then coated the tank with the latest POR-15 sealer. I bought two quarts of the sealer and turned the tank every which way, including rolling it rapidly to spash the sealer around. Then I drained it. I could see into the tank from three separate openings (filler, pickup and drain) and saw no gaps in the coating either by direct sight, or by using a small mirror lowered into the tank. No problems since.

So what is the real answer?? Does acetone clean a scuzzy gas tank or NO?

Acetone is the one I have been using for two months and I don't find any problem.

MurderedOutRides

What do you do when the tank is built into the body on an early car? We used acetone with some success(be careful of fires-no smoking). Someone suggested using aircraft fuel when storing early cars that dont get driven often and that it does not turn to shellac.

I'm doing a science project right now. The car hasn't been driven since '48, about 1/2 inch of tar-ish goo in the tank, and I don't want to remove it. Put in a couple gallons of acetone about 3 weeks ago. Drained it out tonight and flushed with lots of water, lots of brown goop came out, flushed with high pressure washer. I'll be looking with a flashlight tommorow.

I have used vinegar it worked for me, go to sams club and buy it in gallon cases get enough to fill the tank let it sit for at least two weeks and flush it out with water then fill it with gas .

Forget the acetone. I am now a convert of Marine Clean by Por 15.
I tried it on another tank. I used warm water to dilute it 4 to 1, and in about two hours, I had a very clean tank with no gunk at all. It's less toxic than acetone too.