How to clean a gas tank.
 

I tried to take pictures of the before and after but they did not come out.

This procedure is cheap and did an excellent cleaning on my gas tank.

Do all work outside in a nice breeze. Drain all but about a half gallon gas from the tank. Remove gas level float, remove tank.

Balance tank on a couple cement blocks and see-saw back and forth to use the gas to wash as much dirt loose as you can. Drain the dirty gas into a clear gallon bottle so you can be impressed by the dirt you removed.

Add 1 gallon water to tank (hot water is better) and then 1/4 cup of TSP (trisodium phosphate which you can get from any hardware store). See-saw some more.

Add a double handfull of nuts, bolts, screws, etc. and see-saw some more.

Let sit for 4 hours in the sun. See-saw again and again and again until you are sick and tired of it. See-saw some more. Remember, you want those nuts and bolts to run back and forth, side to side to knock everything loose.

Drain water and nuts/bolts into a big pan.

Rinse, inspect, if not clean, repeat the TSP treatment.

If clean, rinse the tank with a 25% Phosphoric acid solution. I dilute Jasco rust inhibitor with 3 parts water for this. Drain and save the acid for other rust removal use.

Rinse the tank well and set in the sun to dry.

Remove the nuts and bolts from the TSP solution and rinse or they will rust. I set the TSP water out in the wind and sun to evaporate. In a couple days, once it is dried out, I will clean the pan.

Have done this many times with motorcycle tanks.I tried this on my M-100 tank..couple pounds of drywall screws..even put it on one end of body twhirler? so I could rotate it but even that was very cumbersome.So,I put 1 gal of Evaporust and about 3 gals of water in it and rotated it every 10 hours or so..3 days later VIOLA...clean as a whistle and no shaking involved.Then hooked up a spare dash light bulb and dangled it inside the tank to get a good look..WOW..rinsed and sealed and good to go.

Not on my truck, but on my other hpbby car. I suspended the tank from the rafters, added some chains and kerosene. Did the slosh things around and drained the kerosene and all was well. I figured kerosene as it is difficult to ignite and would leave a tiny bit of oilly residue which would dissolve in the gas. Worked great. Hanging the tank from the rafters made it really easy to slosh things around and flip the tank over.

Do you NOT use a tank sealer after its clean. Never had to do one of these truck tanks but I've done more than a few motorcycle tanks and I/we have always used a tank sealer.

I am not familar with the term "sealer".


Sealer as in rust arrestor or sealer as in repair a hole or sealer as in a layer of rust prevention material?

The phosphoric acid converts the last remaining rust to a tight paintable surface.

If there is a hole in the tank, I would think you would silver braze it.

If you are suppose to lay in a layer of rust prevention, I pass on that as it will be NOP (Next Owner's Problem).:) I just want the tank to be clean and hold gas until the truck is sold.

I'll see if I can thumb through my papers and get the name of the sealer. Its a two part epoxy sealer you mix and pour into the tank and let it coat the inside. You need to keep rotating the take to make sure everything is coated. I've only used it on motorcycle tanks. It takes a full qt for a bike tank so I can only think it would take a lot more for a truck tank. Again, I have never had to clean out a large tank but I would think it would start rusting again. I'm in the dark about this, but willing to learn.

Here ya go. This is one of the brands I've used. I think this one seals up to a 20 gal tank. Than again, I haven't had to do a truck or car take.

Ethanol fuel will "scrub" a tank over time, but I wouldnt rely on it, unless you tank is in very good shape. I would also probably change the fuel filter a couple of times during the first 6-9 months because trace crap will still be coming out of the tank.

Tank sealer is a crap shoot. Some brands are really good. Some brands are really bad. Some good brands will not adhere properly to the inside of a tank if prep is not followed exactly.

That being said, I would seal it, but follow the instructions exactly.

I agree, some of the quality of the stuff out there is not so good. I would only go with what others may have proved to be sound. I've only had one tank in the past where the sealer came loose from the steal and the company admitted they were having trouble with the material. Its a two part mix and pour. And yes, the tank needs to be 'clean'. This was a very long time ago when that happened and I do believe I got that stuff from JC Whitney. Since than I only use good brand stuffffffff. Guess you pay for what you get.

I took mine to the radiator shop and he cleaned and sealed. Ended up being $75 witch was more than he quoted.