Cleaning Varnish in a Gas Tank at Home and Cheap! Getting Old Cars back on the Road!

Cars that sit for years are fun to buy and revive, but often will have varnish in the fuel system

[@copperhead5216]

I used a 3500 psi pressure washer on my tank. I was able to put a 90 degree fitting on pressure washer wand and get all the surface inside the tank. It removed all the varnish and built up.

[@gavinmclaren9416]

Good video. Just a couple of comments from a chemical engineer. Usually the tarnish and buildup from old gasoline is a result of olefin polymerization (olefins are high octane hydrocarbons from fluid cat cracking units in the refinery), the trace amounts of heavy ends in the gas, and the residue from the detergent/additive package mixed into the gas. Acetone is an OK solvent for this, but I reckon you will get better results from an aromatic such as toluene or xylene. Toluene can be bought from a big box DIY store (my local home depot carries it for about $20/gallon) or sometimes cheaper from a paint store. Incidentally the acetone will do an excellent job of drying out the tank after a water wash. Shake as much water out of the tank as possible and then rince with a pint or so of acetone; it will greatly aid in evaporating the water. I noticed another commentator suggested muratic (i.e. hydrochloric) acid. I would not do that, especially on a rare or unreplaceable gas tank. Hydrochloric acid is incredibly corrosive to mild steel. It sometimes has a corrosion inhibitor included but if you get any into a crevice or fold and don't get it all rinsed out it will be game over for that tank. If you are disinclined to use toluene (or acetone, for that matter), I would suggest a strong base rather than an acid, namely sodium hydroxide, also known as caustic soda or lye. It will dissolve the tarnish and form an emulsion with a little water, which can be easily rinsed out. Caustic is not corrosive to steel at ambient temperatures. It is very corrosive to flesh, though, so all of the safety precautions recommended by OSHA must be considered to be mandatory. The same would be true of muratic acid. A drop in the eye of either would likely mean blindness.

[@318willrun]

Thanks for this input, much appreciated! I actually have never thought about xylene but have used it for different purposes. A lot of good information and suggestions and I'm sure many will find it useful. Thanks again!

[@edsmachine93]

Great idea Tim. Looks great. Good job.👍👍

[@318willrun]

Thanks Ed !!!!

[@WildAzzRacing]

I had the same thing on a '70 Duster back in 2012 that had been sitting since 1986. There was about a half inch thick "coating" on the bottom of the tank that was cracked up like dry cracked soil. I used a 2 gallons of Evaporust (even though there was no rust I could see in the tank) and added a few pounds of landscaping granite (like 1/4" to 3/4" sharp edged pieces), sealed the tank with my homemade plugs, and agitated the tank every hour. After agitating a surface twice I would rotate the tank so the liquid/rock mixture would be on a difference internal surface and repeat. Rinsed it out with water afterwards and used a hair dryer just like you did except I put the open hole pointed upwards to held the water evaporate out. Took less than a day and the tank came out looking factory new inside. You might possibly remember that car as I posted up about it and later sold it on FABO.

[@318willrun]

i can't place the car, but thanks for sharing your process as many will read it and find it very useful

[@musclecarmitch908]

Great video! Great job and information!👍

[@318willrun]

Thanks! 👍

[@jeffsr8300]

I did something similar to my '87 W-150 after replacing the 3rd fuel filter in 3 months I took down the tank, bought 3 bags of marbles at Wally world with a gallon of diesel fuel and shook the you know what out of it, cleared her rite out. Thnx 👍👍🇺🇸🇺🇸

[@318willrun]

Nice work!

[@stephenhotzjustdriveit]

Looking good!

[@318willrun]

Thanks!

[@bobbyz1964]

Couple years ago I used electrolysis to get rust out of the tank for the 68 D200. It worked but took a long long time. Finished it off with a quick hydrochloric acid rinse, then flushed it several times with water. Now someone makes a repo tank for those. 😆

[@318willrun]

Nice! Thanks for watching!

[@BigfootsnMopars]

Sure, NOW you make this video 😂. Good stuff Tim. Thanks for the tips.

[@318willrun]

😅 Thanks man!

[@Doug2114]

I prefer method 237, i like to think out of the box, plus im gluten for punishment! Nice to see another video from you, you must busy!

[@318willrun]

Method 237 is for the BRAVE !!!! Ha! Yes, we be busy!!

[@pauljones2031]

Boiling it out at a rad shop will work very well too.

[@318willrun]

Thanks for the tip!

[@pauljones2031]

You're welcome! I've seen guys use muriatic acid too, but not really a fan.@@318willrun

[@bobbyz1964]

The only trouble with a radiator shop is that they're getting harder to find. When I first started messing with cars, every town with a post office and two bars had a radiator shop. Today, I'm not even sure if there's one with in an hour drive of where I live.

[@pauljones2031]

That's true. The last rad shop closed up here many years ago. I was also thinking electrolosis will work@@bobbyz1964

[@brianschultz5696]

Thanks for sharing. My gas tank has a baffle that prevents me from reaching half of the tank with the brush.

[@user-wk8gg2uj8b]

Use vinegar & soak overnight repeat if necessary with fresh vinegar. And wash it out with baking soda and water. That should do the trick but you also want to seal your tank after with tank sealer because it will rust again and flash rust don’t skip the sealer it will last you another 10+ years

[@jeffdavis5704]

I could be crazy, but i would put some mean green or super clean and let that soak and hit it with a pressure washer.

[@318willrun]

Thanks!

[@trolllibtards2604]

👍🏻

[@larryhutchens7593]

Green stuff? The tanks I have worked on have red varnish in them. It seems to resist lacquer thinner, acetone & alcohol. Back when there were radiator shops I had one hot tanked & that worked quite well but left a lot of brown powdery residue that took a while to completely remove with a garden hose. Never had one with green residue. You are taking a risk using a steel metal brush because it could cause a spark. I would use a nylon or brass bristle brush.

[@318willrun]

correct, no spark ... especially with my arm in there !!!

[@nakedluck11]

How long does it take for gas to turn to varnish? My car has been sitting around for 4-5 years and its fuel injected.

[@318willrun]

I would say..... you got varnish, and bad gas. I would drain the tank if no stabil was added to it before sitting.

[@RejectReality97]

5 years isn't long. Just change the fuel filter a few times the first month of getting the car driving. New gas will dissolve the varnish because of the ethanol.

[@user-wk8gg2uj8b]

Open gas cap and smell tank fumes if it smells like varnish it’s bad don’t run it. You can possibly drain on some cars if you have a drain plug underneath fyi

[@BigMikesHooptyBarn]

Looks like you got er whooped!

[@318willrun]

We sure hope so !!! Thanks Mike !!

[@rexmasters1541]

If you use muriatic acid you do not have to scrub the tank.

[@318willrun]

I have heard that but haven’t tried it yet. I think I will try it out next time. Thanks!

[@rexmasters1541]

I think your safer the way you did it in this video. The acid wash can be hard on you. @@318willrun

[@user-xq6de6yt2s]

Zéro zéro total du bricolage total 😢😢😢