Can anyone tell me how to go about cleaning out an old gas tank. The tank looks solid it just has a lot of old kerosened gas and gunky crud in it.

 

I took my 51F1 tank to my radiator man, he boiled it out and flushed it with steam and pressure wash. Really cleaned up well. It was quite full of "jelled" gasoline residue, and varnish-type gunk. No problem for a radiator shop, and cost me very little.

 

My 58 ford sat for 19 years and it had some CRUD in it!!! This might not be the best way to do it but it worked for me. All we did was take the gas tank out and pour in some dawn and fill it about half way and shake it around alot. It took us about two hours to get it clan but I ain't got nothing in it anymore. The best way to do it though would be to go to a parts store and get a professional cleaner and a sealant. I know that they sell a cleaner and a sealer for old tanks in J. C. Whitney. Hope this helps you--jaxxx

 

I took mine to the radiator shop a few years back and had him boil it out and put some sealant in it just in case there were little holes in it.

 

Guaranteed, sure fire way to get your gas tank clean as a whistle; take the fuel gauge sender off. Close the drain valve. Add about 3-4 gallons of water. Now dump about 4 ounces of Red Devil lye drain cleaner in there. Slosh it around to mix the drain cleaner, then let it sit for a few hours while you make a new gasket for the fuel gauge sender.

I did this twice and the tank came out clean, bare shiny metal inside.

Best regards,

 

Thanks a lot for all the suggestions. They all sound good!

 

With regard to the Paul Menten (pcmenten) method: Does this remove surface rust inside the tank as well? Obviously one would have to remove the tank to pour out the solution through the fuel gauge sending unit hole to remove any scale and rust that would not pass through the drain hole.

 

Whoa! You've got scale that won't go through the drain? Wow.

I would give it a try. If rust is Iron Oxide (Fe2O3) and lye is Sodium Hydroxide (NaOH) it might dissolve the rust scale - Fe2O3 + NaOH = H2O and Na3Fe. You'll end up with a salt water.

After I rinsed out my tank, I put Marvel Mystery Oil in it to help prevent new rust. I was able to install it and get the truck running in a couple of days, so I filled the tank right away to help prevent rust.

Best regards,

 

Yep. I took the eaysy way out. Just dropped the pet **** and gas line, and took out the threaded piece into the tank, fitted a plastic tube of about an inch to it, rethreaded so it would be above the settled scale. Work very well, but I will eventually have to clean the tank. Your chemistry seems right on. I will save this info and do it this winter. Thanks.... f-3 Brien

 

Whoops. I goofed the chemistry here.

>- Fe2O3 + NaOH -> H2O and Na3Fe

Iron won't combine with Sodium, they're both metals and both have positive valences; Sodium +1, Iron +2 and +3.

To dissolve rust will require something like Muriatic acid (HCl).

6HCl + 2Fe2O3 -> 3H2O + 2FeCl3

I was cleaning some 56 Fairlane parts today and thinking about the chemistry when I realized my mistake about rust and lye. Sorry for the confusion.

To recap; soak the tank with Lye to clean the old gas varnish out, rinse, then use Muriatic Acid to dissolve the rust. Be sure to dry the tank as best you can, then slosh some oil around in it to inhibit new rust from forming.

 

Alright guys...I bought muratic acid anyway as no one around here had lye. I let a couple of gallons sit in it and kept sloshing and moving it around for a few days. Then I poured it out and looked inside after rinsing. I still had crap plastered to the sides of the tank. So I took my pressure washer and hit it best I could by sticking it inside thru the float hole. That got rid of alot of stuff. However I know I did not thouroughly clean it..I have abandoned the cleaning project and purchased a poly replica tank for $200. I would rather be safe than have problems down the road. Thanks for the input. Just thought I would let you know how it came out. The acid did do some good just not as clean as I wanted.

 

Ok Capn: Where did you locate the poly tank? I could only find a stainless steel one @ Mac's Antique Auto Parts for around $500.00 So, I explained in one the above messages how I solved my problem with a small one inch plastic tube. It just leaves an inch of gas on the bottom of the tank all of the time. Lets the scale settle to the bottom of the tank. I know it really is only a temporary fix but I saved $500.00 on a new SS tank. I figure as long as I keep sloshing the fuel around then it won't get too old and cause problems.
I would like to know where to get the poly tank though. I may want to put it upon the shelf for future use. Thanks F-3 Brien

 

There is another method for removing rust and scale from tanks that tractor guys use. I have used it a couple of times and it works great. Unfortunately, you need a tractor. You take your tank and use tie down straps (rope, duct tape)to secure it to the center of your rear tractor wheel. Jack up and block that wheel. Put a few handfuls of rocks, bolts, nuts, nails or any sharp hard objects in the tank. Start up tractor, put in first gear and let idle for a few hours. Tank and contents tumble (like a rock tumbler). Presto! Shiny well scrubbed tank. Sealer is then recommended. Wonder if it would work with a lawn tractor? Oh yeah, be careful of sparks and gas

 

I have heard of this method only using a cement mixer. I suppose any motor driven wheel that turned slowly enough and had the capability to secure the fuel tank to it would do. I would be careful with rocks and nails, better to use small stones, pebbles, mix in some sand or other grit, etc. I think you are just after the abrasion effect against the interior of the tank. F-3 Brien

 

Just got the cab off last weekend and looked at my gas tank, what i thought was caked on mud turned out to be some underbody sealant that somebody has caked on. Was wondering is it safe to sand blast the tank? I am getting ready for the frame to be blasted. I have heard mixed things on sand blasting, stretches the metal so dont use it on the sheet metal parts, will this happen to the tank as well?

47 years of dirt and grime about to go bye bye.

Thanks and have a great one
Coach J