Cleaning gas tank

SDW · Post by **SDW** » Sat Aug 06, 2011 10:44 am

Anyone have suggestions on what to use for cleaning inside of a gas tank? My M38 jeep sat for about 20 years and the gas was still in the tank. Now we are trying to get it running again. Thanks!

evanso1975 · Post by **evanso1975** » Sat Aug 06, 2011 12:30 pm

Try this:

http://www.frost.co.uk/automotive-tanks ... clean.html

It's a US-made product, so it should be readily available at a store or online seller local to you.....

Wbr,
Owen.

oilleaker1 · Post by **oilleaker1** » Sat Aug 06, 2011 2:29 pm

I have a bodyshop friend that let me use 5 gallons of reclaimed paint thinner. It dissolved the old gas varnish quite well. Then I simply gave the dirty thinner back and he reclaimed it again. I also soaked the in tank filter and carb parts with it. No disposal problem that way!

John

Oldsalt · Post by **Oldsalt** » Sat Aug 06, 2011 5:25 pm

When I clean one, I use solvent to get the oily gunk out. Dispose of that like used oil from the engine. Then I use my pressure washer to blast the inside of the tank clean. I rig a 90 degree ell on the nozzle so I can direct the water blast into every corner and I keep washing till it looks completely clean inside. It will really do a number on any rusty residue on the inside. Then just let it air out to get completely dry inside. If you are in a hurry, you can rig a light blow of compressed air to speed the drying.

Post by **wesk** » Sun Aug 07, 2011 10:17 am

Or just haul the tank to your engine rebuilder or radiator overhaul shop and have them hot tank it for you.

Balvar24 · Post by **Balvar24** » Mon Aug 08, 2011 7:43 am

This is what I did. I patched the holes with some super duper aircraft tank sealant that I believe Wesk recommended. Is there any need to treat the inside of the tank after having it tanked?

Post by **wesk** » Mon Aug 08, 2011 9:44 am

The only treatment guaranteed to last a lifetime if properly operated is bare, clean metal. The reason these tanks have finally rusted is moisture. This moisture was allowed to accrue while the jeep sat inactive for long periods of time with little or no gas in it. If you don't want the tank interior to corrode you must keep it covered with fuel or something like misting oil. If the jeep is being parked for more than a week or two the simplist thing you can do to keep moisture off the interior of the tank is fill it up.

I have been fixing fossil fuel burning critters for over 50 years and I can assure you I have seen every paint on tank coating fail at some point. When they fail their coating starts to separate and the shreads of it clog the filters. If you get goose bumps all over about a certain new "Guaranteed for the life of the tank" coating system then most likely you will ignore all the old timer warnings and buy it lock, stock and barrel and 10 or 15 years from now whomever owns the jeep will not have any recollection of these warnings.

The whole thing about "Age, history and experience" and "Learning from it" it is ignored every day by millions of the blinded masses!

SledDog · Post by **SledDog** » Sun Sep 04, 2011 3:05 pm

Thought I'd bring this back up. I have the same problem, a tank that has been sitting with what used to be gas in it since about 1982. Its acquired quite a unique aroma and texture! The exterior of the tank seems to be in great shape, no rust.

looking down the fill tube, there appears to be some sort of white bag. I have foam in my fuel cell on my crawler. Does this "bag" serve the same purpose? Is it supposed to be there?

Before I send it off to get cleaned or attempt it myself, what's the best way to dispose of gas that's in there? Can I just open it up and let it evaporate?

thanks.

oilleaker1 · Post by **oilleaker1** » Sun Sep 04, 2011 5:06 pm

Sleddog, the white bag may be the brass filter screen depending on what kind of Jeep/tank you have. The M38 had a filler extension that slides up and locks or rotates and comes out. The extension has the filter soldered in the bottom and is part of the extension. The M38A1 has a screen that sits down the tube at the bottom on a lip. You lift it out by hand. I either kill some bad driveway weeds with it or send it out with waste oil. Some guys have waste oil heaters, but don't want any sediments or water. If you can thin it out on a pan or plate and let it dry, you can just throw it out in the garbage like dried paint. My stuff was recycled at the bodyshop with the thinner I returned. Their reclaimer deposits it in a bag that get tossed when dry.

SledDog · Post by **SledDog** » Sun Sep 04, 2011 6:02 pm

Thanks, its an M38 tank. It looks to have the extension you mentioned. I'll throw on some gloves and see if I can pull it out. Killing weeds sounds like a good idea, I certainly don't need the heater! It was 110 here in AZ today.

SledDog · Post by **SledDog** » Mon Sep 05, 2011 3:06 pm

Ok, there is definitely a sleeve and a filter down the filler neck of the tank. Is there a trick to pulling that sleeve out? I'm guessing its just seized in which case I'm hoping shooting some brake cleaner or PB blast down there will help.

Thoughts?

ocwd · Post by **ocwd** » Mon Sep 05, 2011 7:28 pm

I used lemon juice. Put it in and let the tank sit over night. Rotate and let sit over night. repeat. Neutralize with water and baking soda. Then coat with oil if it will sit for a long time. Slosh it around to get the chunks to flow out. You may need several large bottles. It's pretty cheap stuff and a natural acid.

Dave

oilleaker1 · Post by **oilleaker1** » Mon Sep 05, 2011 9:04 pm

I used a pair of snap on needle nose pliers, grabbed the upper inside lip of the extension and worked side to side and back and forth in a turning action with lots of re-claimed thinner and it broke loose. Took a little working it to get it up and out. I put it in my glass beader cabinet and blasted it. Came out very clean and nice. Looked terrible at first. After I rinsed and dried the tank, I sandblasted it, inside and out, and soldered up all holes. Primed and painted and it's ready to go again!

John

Post by **wesk** » Mon Sep 05, 2011 9:42 pm

Just a reminder that filler tube slide-up screen has three small nubbins at the bottom that ride up in the three grooves in the filler pipe and then you must rotate the slide-up screen a few degrees CCW to finish pulling it out.

Cleaning gas tank

Cleaning gas tank

Gas Tank