Does anyone have suggestions on cleaning the black tar out of a fuel tank on a 27 coupe. Many years ago I'd used a gas tank sealer sloshed around inside the tank. I don't know if thats what I'm seeing or old fuel residue. The sediment bowl was completely gummed up but came clean with carb cleaner. No flaking or rust visible. Car has been out of commission for 20 years. Thanks
That sounds like a pretty bad, hard to remove material coating your tank. Here is what I would do. Buy a female plug for the tank drain. Put a couple of handfuls of small, smooth river rock pebbles in the tank then, purchase a gallon of paint remover (liquid, not gel), pour half of it in, slosh it around thoroughly, several times and let it sit and work between sloshes. After it has done itsí work, rinse it out and clean the pebbles off. Put the pebbles back in and do it again with the remaining paint remover.
After doing it again, there may be a residue. If so, purchase a gallon of lacquer thinner and pour in half and slosh it around and let it work. If it needs to be done again, use the remaining lacquer thinner.
Wash out with water and dawn and sit out in the sun to dry.
When I did mine, after cleaning and exposing the bare interior, it had a coating of rust in it. For that, I poured in a 50/50 mixture of Muriatic Acid (1 gal. Acid to 1 gal. water) and let it sit and work. After a day or so, the rust had dissolved so, I poured out the acid, rinsed and poured in a strong mixture of baking soda and water to neutralize the acid. After the soda water did itsí work, I quick dried the tank, using a heat gun. Once dry, I poured in a quart of silver POR 15 and thoroughly sloshed it around until the entire interior was coated. When I poured it out into the can, there was a 1/2 quart left. Be careful to thoroughly clean the threads of POR 15, for once it has cured, it is rock hard. I did my tank in 2010 and after almost 9 years, the POR 15 is still working superbly in protecting the interior of my tank. Jim Patrick
PS. Instead of pouring harmful solvents on the ground, Get a large funnel and pour the dirty solvents back into their containers and seal and discard safely. You will have some left over which you can pour into spare containers such as old paint cans or Clorox bottles.