skruffy Dork
6/25/08 7:54 a.m.

I pulled the gas tank out of my new 70' 240z project (I'll make a post about the car later) last night and found some slight surface rust inside. Not anything bad, just a sort of wet and powdery rust residue from where a little bit of gas had sat for 20 years. Anyone have any experience getting a tank repaired or using one of those epoxy lining kits? A quick google comes up with this. I call upon the vast wisdom of the GRM forums to guide me down the path to unclogged fuel filters and happiness.

Also, I need to replace the rubber fuel lines and whatnot as well. One of the vent lines was so brittle it broke off when I touched it lolz.

914Driver HalfDork
6/25/08 8:24 a.m.

I've used Metal-Wash to clean the tank and some liquid white stuff from Eastwood at least five times. Once on a '52 Dodge truck and about every Jap bike I've owned.

Metal-Wash removes the hazy layer of built up varnish and skuffs the rust. The whit stuff seals it. NEVER any trouble after that. Replace any lines you can while it's out, it's tougher to do later on.


I still have the original 7oz. can that has done five tanks.

stuart in mn
stuart in mn Dork
6/25/08 8:28 a.m.

If the rust is only minor, I'd see about finding a local radiator shop that will boil the tank out. I've always been a little leery of products used to line gas tanks; I'm sure many of them are fine but I picture the lining eventually coming off and clogging things up.

6/25/08 8:45 a.m.

After removing my tank (1987 FX16 GT-S) I soaked it with Naptha for a few days, turning the tank each day. Then drained it out and pressure washed the inside. Let it dry in the hot sun, then rinsed with acetone to remove any residual moisture. Looks great! Not sure if the Naptha loosed up the 'varnish' or not. You might try pressure washing first.

If you use treatments that etch the inside of your tank, you could open up some pinholes which would require a sealant.

foxtrapper SuperDork
6/25/08 3:50 p.m.

Epoxy kits in gas tanks made me a lot of money over the years. They flake off nicely, clogging fuel filters, pumps and carburetors. Many a motorcycle came to me to have the liner removed and the damage repaired.

Light rust inside a gas tank is 100% oem normal. From the day it was made it had flash rust inside. Only if it starts plugging up filters is it a problem.

If it really is too much, something like vinegar will disolve the rust and be easily washed away.

slefain Dork
6/25/08 3:58 p.m.

Dump in about 5,000 bbs, shake it like a polaroid picture, dump out bbs, rinse tank out and let dry. Just keep it full of gas and the rust won't come back.

oldopelguy HalfDork
6/25/08 10:20 p.m.

Instead of BBs, drop in a short chunk of chain or some nuts and/or bolts. That way you don't have to worry about any of them staying behind and clogging a filter later because you can see everything and fish it out easily.

The 3-part clean/seal/coat gas tank kits from reputable companies have always worked excellent for me. I've done at least a dozen cars and twice as many motorcycles without a single issue, and one of those cars has been a weekend driver for almost 15 years.

problemaddict New Reader
6/26/08 4:49 a.m.

If you have time/patience, Electrolytic Rust Removal is the cheapest/easiest way to remove rust from a gas tank...IMHO.

You can follow this link:

with some slight variation to do a tank. You fill the tank w/ water and the "Super Washing Soda" that you can get at the grocery store. Fab up a rod of some sort to insert into the tank without it touching the sides. Then attach a cheap battery charger to the tank and rod. Follow the link for the proper polarity. The rust will "magically" move from the tank sides (cathode?) to the rod (sacrificial anode?).

I did it to this motorcycle tank that had BAD scale-rust. it took 48hrs to get from 'nasty' to 'slight surface rust'. I could have kept going until i got to clean metal, but it will be a while until this bike will need a gas tank, so i'll finish up then....



Setup w/ cheap Harbor Freight charger and spray can anode support:


After 24hrs:



After 48hrs:



Its a pretty neat process. Be sure to use some sort of short-out protection. The rust can build up on the surface of the water and cause a short between the rod and the tank. This didn't happen to me, even with all that gunk floating that you see in the pic, but i guess it could happen w/ enough time. I used a power strip w/ built in breaker to plug the charger into....


Ian F
Ian F New Reader
6/26/08 4:17 p.m.

We used the POR 15 gas tank sealing system on a Diamond T tank... It took two days of following the directions to the letter... From what I've heard, you'll have flaking problems if you don't let the inside of the tank dry completely before dumping in the sealer. We focused a 500w work light on the outside and put a hair-drier in the sender port overnight.

That was a nice Spring weekend I'd like to have back... but it did seem to work well... but in this case, we had few other options... where do you find a replacement tank for a 1 1/2 ton Diamond T?

For our Volvo 1800ES, replacement tanks are available for $500. We went that route.

Many radiator shops will clean, test and fix gas tanks. I was going to tank my own Volvo's tank to my local shop before I decided to sell the car.

ddavidv SuperDork
6/26/08 8:43 p.m.

I'll ask the obvious yet unasked question--how much is a new tank? Some of these whiz-bang may-work chemicals can cost almost half as much as a repro tank.

skruffy Dork
6/27/08 8:35 a.m.

The tank isn't in bad enough shape for me to even consider replacing it. It's honestly got a little strip about 4 inches wide of surface rust inside the tank that I just don't want to risk running through the carbs.

SoloSonett None
6/27/08 9:02 a.m.

I had the same issue with the Sonett. Back in 02 After sitting for 2 decades, the tank was a filter clogging nightmare. POR-15 tank kit did the job. ( follow the instructions to the T!)

It's still in perfect use in GA , now

Jack SuperDork
6/27/08 9:23 a.m.


This sounds like some suface rust only and I believe you are making this too hard. There is nothing wrong with an unlined tank in a car that is used regularly.

Throw a chain in there with a little bit of water, rattle it around for a while. Spend extra time with the rusty part on the bottom, so the chain works that area well, while you shake the tank. Then rinse several times. That will get rid of the flaking rust. Blow out the inside with a hair dryer or heat gun for several hours, then use a filter on the fuel line. With the first gas in the tank, add a bottle of fuel line anti-freeze (ethanol). to insure all the moisture is out of the tank.

I hung my TR8's tank on a rope to make it easier to shake, without having to hold the full weight of the tank the entire time.


SoloSonett New Reader
6/27/08 9:47 a.m.

I had the same issue with the Sonett. After 2 decades of sitting idle, it was a filter plugging nightmare.

POR-15 Tank kit did the trick! ( followed the instructions to the T! Long sun drying sessions )

It's still in great service in GA

YaNi New Reader
6/27/08 6:40 p.m.

Eastwood also sells a fuel tank sealer that works very well.

M2Pilot New Reader
6/27/08 9:26 p.m.

PO of my M2 used POR-15 in my cars' tank several years ago & it's still doing fine.

Autech510 New Reader
6/28/08 10:27 p.m.

Another happy POR-15 customer here. Going on 7 years since the treatment... -Ted

6/18/09 3:43 p.m.

There are some new rust removers out there that remove rust without scrubbing. Have you heard anything on those yet?

MiatarPowar HalfDork
6/19/09 8:46 a.m.

I had the tank from my '69 96 DeLuxe professionally dipped, then sealed it with the POR-15 tank sealer. No problems after nearly 2 years.

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