Pulled the tank on the old Cosmo today. All I can say is WOW....

Must have dumped 6 gallons of nasty old fuel out! Tank looks crusty inside, but is beautiful outside.

Any recommendations based on experience to help a brother out? Its not like I can get a replacement, and a fuel cell is a bit much.

Oh, cleaned and tested the sender, its all good!

cleaning tank
 

my cousin has the same problem. He went to a performance auto parts store and they gave him a place to go to have the tank clean and sealed. My suggestion is go to your local performance auto parts store or a speed shop they might have some place they go to have their tanks cleaned and sealed. He's my cousin had the work done in Connecticut where we live. So I hope this helps you .good luck , carlosrx3

Alot of radiator shops do fuel tanks aswell... I had the one in my rx3 done here in NC at A place called Breedlove's Radiator shop. They did a great job... It not very expensive either

Yup, they open it up, clean and paint it with a rust proofing. Then make sure they pressure test it for leaks!

Don't want to mount back up and have to take it down to seal up etc

I've been calling around, with no luck. Radiator shops are almost non-existant around here now, and the ones that are still open won't touch a fuel tank anymore.

I am going to call some 'restoration' shops today. Surely they know where I can take it, or can do it themselves.

Por-15 fuel tank kit. Thats what you want.

It works great. Used on on the crustiest fuel tank ever on an RX2 that had been sitting since 1980-ish.

Like 7dust says, get some POR15 Fuel Tank Kit. Worth a try. I will be using this on my RX3 tank fairly soon.

Here's the link…

Fuel System Restoration

I'm getting ready to do my tank, pretty much the same thing as you djmtsu. I've seen the vinegar for a couple of weeks method works well. I'll give it a go to see what happens.

It just occurred to me that I have several gallons of Evapo-Rust. I love this shit. It works so well, is safe for the environment (unlike the car :) and has little to no odor.

I am going to dump it all in, seal the tank, strap it to my engine stand, and rotate it every couple hours for a few days.

Wish me luck.

So far, so good.

I have a bucket with 1 gallon of Evapo Rust in it for soaking parts, and 5 gallons in the tank.

I have soaked the filler neck, and the fuel level sender. 24 hrs each. Both are minty fresh and clean! Its incredible.

The tank is ongoing, rotating it every 8 hours to get it all soaked. Should be ready to drain and repeat over the weekend, and hopefully go back into the car next week. Judging by how well it has worked on the other fuel pars, I have no doubt the tank is going to be perfect when done.

Sorry, no before and after pics. Didn't even think about it.

If it don't work. I may know someone with a gas tank I let you know next week

I know people with Cosmo/RX-5 tanks, but they are hoarders :)

It is looking like this one is coming clean. So far....

[Q UOTE=djmtsu ;11699607]I know people with Cosmo/RX-5 tanks, but they are hoarders :)

It is looking like this one is coming clean. So far....[/QUOTE]

that's funny being a hoarder for rx5 a Cosmo because there's not too many people out there redoing cosmos. I was telling some of the guys in my club out hooking up a Cosmo they all laughed at me. If I can find a good body don't care of it runs or not. I do It with a 20B. I like to find a automatic with air set up and sit back and chill out for the summer time and my boys are sweat in the car driving around 100 outside happy in my car rocking it Nice cool and If you know anybody has a good body car interior let me know send me a private message. Good luck

I used the por15 kit for my repu tank great stuff sets up hard as nails took 2 weeks to come off my skin.

This tank should not need a reseal kit like POR15.

After some soaking/rotating of the tank, the sludge is just wiping off with a paper towel on the end of a screwdriver. Metal underneath is shiny as new. The tank also does not leak, the exterior is in perfect condition. It would seem like the 'rust' was just varnish from evaporating fuel. Also note, that I am not using harsh chemicals (like Marine Clean, or any harsh acid).

Not sure if this will help djmtsu, but check this out!!!
Auto Gas Tank Sealer Kit - Gas Tank Sealer - KBS Coatings

I would also throw a short piece of tow chain in the tank . This will help break loose the crusty bits .

Just starting to play with Evaporust myself. Wow. Amazing stuff. I'm gonna use it on my tank too. So glad you mentioned it.