No, not that I can imagine and I've dealt with a few.

 

Oh well

Thanks for the confirmation, time to stop being lazy.

 

I'm not saying it couldn't be done and hasn't been done by folks in the past, I'm just saying it's a temporary fix at best. Take the tank out and take it to your friendly radiator shop and get them to clean it out.

You should never have to worry about it again.

 

Easier to do it right and pull it. I've hit critical mass for being tired of replacing fuel filters

 

Mount the car on a rotisserie and spin the whole thing around.

 

I'm pretty much a novice still at wrenching and I recently pulled the tank and cleaned it...it wasn't too difficult. As usual, just make sure you see where stuff goes when you need to put it back. The S4 manual describes the process to, not sure if your model year does, but its easy enough.

 

Thanks Hector.

 

This is what I did to my tank:


1. Took the tank out. The hardest part of this was dismounting the fuel filler neck. Its awfully inflexible and very tight, but it will come off.

2.Dismounted the fuel pump and sender, which involves a bit of careful articulation to remove the pump. You have to be careful of the attached strainer, and the float when it comes out of the little 2-3 inch hole its mounted in.

3. Emptied the remaining gasoline into a 5-gallon bucket and dumped it at the local dumpster in their hazardous petrochemical bin (free!)

4. Washed the remaining gas residue out with dawn and hot water. Repeated this process several times.

5. Purchased a gallon of muriatic acid at the hardware store. Poured a solution of muriatic acid and water (50-50 mix) into the tank. You'll need chemical gloves, you'll need to do this in a very well ventilated (outdoor) area, preferably with the wind blowing and even then you may want a respirator, because this stuff isn't fun to breath.
Muriatic acid melts rust (and metal, as all acids do). So after a few soakings in acid, the rust in the tank is gone and is replaced by bare metal. Dump the acid on concrete if you have any stains on your concrete and then wash the area with plenty of water to neutralize.

6. Neutralize the acid in the tank (quickly) by flushing the tank with water, then with a little bit of baking soda and water after you wash it a few times.

7. Buy a suitable tank liner from the auto parts store. Its like a paint that you will pour into the tank and then roll the tank around and around to get it to coat the full interior of the tank. After about 48 hours of drying time, you have a freshly lined fuel tank that will never rust again. Its actually better than buying a new tank, because even new tanks will eventually rust. One that is epoxy lined will never again rust.

 

Nice work Brent, thanks for posting your steps. That will take care of it for a long time - agree!

 

Its probably the only permanent solution to the rusty tank problem.

 

Agree Brent. This is my SOP on the British cars, was just being lazy here. I'll pull it and do it right.

Thanks!

 

Research the tank liner products carefully, there is a lot of different products out there and people are getting mixed results.

You should be able to do a search on the BB for them.

 

How much does a new tank cost?

 

Usually around $185.-

 

If I bought a new tank, if it was steel, I'd probably still put a liner in it.

 

+1, small amount of additional work for peace of mind and longevity.

 

The only thing you have to avoid after lining the tank is certain additives. Ketone and solvent additives especially. Any petrol-based additive is fine. Techron and Seafoam are two of my favorites.