Got bad gas tanks, musta sat for a while

[Mike]

So I got some ancient relic 89' e30, and it has been dormant for quite some time. I'm not close at all in terms of firing up the ole' m20. I take my covers off my back seat, and remove the level sensor, and peer inside the tank to find some aweful looking shit, maybe it was called gas a few decades ago, but to me it looks like a combination of barnacles and peat moss. I'll try and get a couple pics up on sunday.

So, I gots to thinking the tanks gotta get drained, removed from vehicle, and then? Replace with brand new OEM tanks, or are there shops that can bring my stuff back from the dead. This is hopefully just a marginal setback.

Of course both tanks got the certified lift arm impact damages too, which I'd love to take care of at the same time.

[bmwpower]

I've heard of shops that can totally restore them. What's the price of a new one? Not sure on the cost to restore...

[Mike]

I did a search and somebody's post was talking about radiator shops can bring em' back by boiling the tanks. It sounds like an option to me, but anybody else been down this road?

[kway]

Last summer I got an old Aermacchi (motorcycle) for free. Only 600 miles on it, but it had been sitting for over 20 years. There was a good 1/2" of varnish in the bottom of the tank, I thought it was a goner. Figured I didn't have anything to lose by trying to save it though, so I dumped a quart of acetone in there and a bunch of (new) random nuts and washers I had. Sealed it up and shook the whole mess up by hand for the better part of an hour, changing the orientation occasionally so the hardware and acetone could work all the sides.

I couldn't believe how well it turned out. all the varnish was completely gone leaving the tank nice and clean. Of course, you're talking a much bigger tank, so it would be a lot more acetone, hardware, and a helper to agitate it all. Plus the baffling in there and the way the tank is split, definitely more complicated, but it's a cheap experiment to try.

[Restoman]

I don't know I don't even want to look in my tank.

[jlevie]

If the only problem is old gas, a drain and refill with fresh, plus a heavy dose of Techron, will suffice.

But if the tank is heavily rusted with a layer of sediment in the bottom, a more aggressive remedy is required. You can replace the tank with a new one, or clean and seal the one you have. Provided that there's no physical damage to the tank or pinholes cleaning and sealing is all that's needed.

I have tried having a tank dipped, with poor results. The internal braces and such in the tank tend to trap particles that won't be dissolved and removed by the dip process. I was able to completely clean the tank by by sloshing a half gallon of a 1:3 mix of masonry acid and water in tank followed by flushing with plain water. Each acid cycle lasted about 45 minutes, or until the acid was fairly well depleted. It required all of one Saturday and part of Sunday morning to get to the point that no more rust came out of the tank when flushing with water. The sealer that I used is the one that Eastwood sells.

To do this one has to fab up a seal for the sensor/pump so that you can invert the tank during the acid wash and sealer application. Baggies and rubber bands can be used to seal up the tube openings. And when flushing the tank you need to catch the water in order to tell if rust particles are still coming out (I used an open topped yellow oil catch pan).

Total cost was only about $70 and it wasn't hard to do. Time consuming, but not difficult.

[Mike]

Thanks alot on the pointers guys. I'm at least going to remove this tank and try flushing it. The car is almost ready to send to the painter anyways, so it can occupy my time while thats going on.

[Restoman]

Is there a drain plug on our tanks? My gas if at least a year old. 8 months ago as an attempt to lessen the trouble I put some fuel stabilizer in.