Cleaning tar from a fuel tank

Bought a 1972 Karmann Ghia coupe, it has set in a garage for 10+ years and then in a barn for another 10+ years. Decided to get it running. Began by removing the fuel tank & fuel sender. The tank is intact but there was about 3/4 inch of tar in the bottom after I dumped the liquid out. I put a quart of aircraft paint remover in the tank and left in overnight. The next day the tar wasn't solid but very sticky. Poured out what I could and used a 1500 watt hear gun on the outside of the tank for about an hour. If you do this make sure you are in a well ventilated place because the fumes are terrible. Then I put 2 more quarts of the aircraft paint remover in. This time I got to bare metal. Took it to a car wash and you wouldn't believe the trash that came out of the tank. I have ordered a new fuel sender and have replaced the copper sleeve at the fuel tank supply/exit. The fuel line was partially plugged with tar and I used break cleaner. I would fill it and then use air pressure to blow it out. It took 3 cans before it came out clean. Will post as I proceed.

I had the tar /varnish cocktail in my 250 after sitting for 6 years. I tried cleaning it with brake cleaner, laquer thinner, and Simple Green. I kept getting crap into the carbs to the point that it actually shut the car down.

I gave up and spent the $70 or so to have a rad shop clean it out and seal it up. I still had to flush the fuel line back and forth several times with the laquer thinner until it finally cleared up.

Good luck with your cleaning process.

i couldn't find a radiator shop who would do my fuel tank, so I taped up all the openings except the filler, then dumped a gallon of acetone in it. shook it around, poured it out, strained it, poured it back in, etc. got everything out with just one gallon of acetone.

This thread is relevant to my interests. I just pulled Ugly's tank yesterday and there's a ton of crud inside it.

I have ordered and received a new fuel level sender and an electric fuel pump. Will begin re-assembly as soon as it gets a little warmer. My barn is not heated.

Currently doing this to a 1982 Diana fuel tank.

Repeated swish with gunwash (pretty much lacquer thinner but way cheaper) with an occasional steam cleaning in between with a rented industrial steam cleaner.

It's been a week but I think I've got it all.

Shawn