I was at Pep Boys today, and I asked one of the mechanics there what he would do about rust in the gas tank. He said he had something that would clear the rust and junk in the tank, lines, and carb all in one shot. He gave me two 15 oz. cans of "B-12 Chemtool" and told me to dump that into my tank along with the 7-8 gallons of gas that were already in there. Then after about an hour, rock the truck (thus shaking the gas in the tank) and mix up all the chemicals and initiate the process of destroying the rust. He said do this a few times periodically and then let it sit overnight. During this time the Chemtool would actually eat up all of the rust, leaving you with a clean tank! When you ran the truck, the lines and carb would be cleaned as well. The guy said he'd been doing this for 42 years and that it hadn't failed him. Has anybody else ever done or even heard of doing something to this extent? Tips? Advice?

 

I don't know about that, I've never tried it, but I would mock it up on the bench with a little gas, some rust and some chemtool and then shake it up and see what happens. Otherwise, just leave the ole gas tank alone - unless your fuel filters are constantly getting plugged.

 

It does sound fishy but here's what I know. I had a big problem with rust in my tank. It would plug my fuel filter and the truck would die. So I asked my neighbor, who is a college chemistry professor, what I could do about it. He said you need Hydrochloric acid (naval jelly) to remove it. You can get it in the hardware store and when you're done you neutralize it with baking soda but he thought it may be dangerous. So I don't see how 30 oz of some gas line cleaner can do the same thing as HCl. You can also buy a kit for this from some company called POR. The kit is like $30 and comes with a tank liner that you put in there afterward. I've heard good and bad about the liner from guys in this forum. If it holds it's great but when it comes undone from the inner walls of the tank then you're problem is worse. I didn't like doing this cause it seemed like a good deal of work and the expense was still $30 and it may or may not take. Another option (which I was gonna do) is to take it to a radiator shop and they'll hot tank it (soak it in acid) and it'll come out shiny clean. It may take a couple days but it's probably worth it. A local shop here was gonna charge me $100 to do it. On my way over there I stopped by the local salvage yard and checked the tank on the truck I had been pulling parts off all these months. I assumed it would also be rusted but it wasn't. It was shiny clean on the inside. I paid $55 for it. When I posted this another fella here says he sees them clean all the time. So I think this is your best bet.

 

Well, here's what I do, I got tired of the trash & just removed the tank, took the sending unit out & rinsed the tank out. I have taken something like marbles & put them in there & shake it up to knock stuff loose in there. It doesn't take that long to remove the tank, and it worked for me!!

 

That B-12 Chemtool is great stuff, I have used it for years. It will totally dissolve varnish in your fuel system and carb, but I have never known it to eat rust or dissolve rust. Do what bronconut suggests, empty the tank and remove it, clean out whatever you can with a hose or pressure washer, and then put some rocks or something in it, and with a helper, shake the tank back and forth to loosen everything up. Empty it out and repeat a couple of times. After I cleaned mine that way, I coated the inside with this "gas tank sealer" from JcWhitney for $30. I don't know if it was worth it or not but it gave me some peice of mind to coat it.