docmirror

If the tank is plastic, there are a bunch of chemical methods for cleaning it. The problem is will it harm the plastic of the tank in the process. Since the less inert the cleaner, the more likely it will be to harm the tank, finding the right mix is important.

What's mostly in there are the byproducts of the fuel that was left. This is going to be a bunch of varnishy type old aeromatics that didn't evaporate like they were supposed to. So, probably start with some good ole turpentine. It's a solvent, so it will loosen the varnishes stuck to the inside.

I've also used the pebbles in suspension method and it works fine. Once you pour out the old turpentine and pebbles, use plain hot water and soap inside, then flush with hot water. All the pebbles will come out, don't worry.

If you know the level of the stuff(I hesistate to call it fuel) that was in the tank when put up, try to fill the tank to a higher level than that. There's a ring of goo/crud at the line where the old liquid was. It's important to get that line under cleaning fluid. Orient the tank in the way it sits in the car for sloshing.

There are aircraft products that clean and reseal, but I've heard both good and bad about them, and don't know if they are suitable for plastic.

kary4th

I just drained 12 gallons of 18 year old gas out of mine. Everything in, on and around the tank is coming out this weekend.

Have you run into any problems (other than what's already mentioned here) that I should be watching out for?

Chuck Z

I will not know for sure until I get the car back on the ground and start it up again. It's been on jack stands in my garage since July when we bought it (been cleaning and replacing corroded parts). I will say, the day I put it up on jack stands it wasn't running very well. When the engine would reach 2k rpms it would start to run really rough. Needless to say, this will be the first thing I dig into once its back on the ground. Based on how long its going to take to get the sending unit (5-6 weeks coming from Germany) its going to be a while before I find out.

Keep us posted on your findings.

jpitman2

Just be careful trying to unscrew the intank filter/pump.....if too tight or stuck, can spin the threaded insert, and then its difficult.
jp 83 Euro S AT 48k, BTDT.

Chuck Z

Ignorance really IS bliss! Sure glad I didn't know this when I took mine out, it was REALLY snug.

Dennis Wilson

Chuck,

The rough running above 2K is probably due to a film of shellac in the upper cylinder of the fuel distributor.

Dennis

Chuck Z

Dennis,

Tell me more.

Chuck Z

Remember, I'm very much a novice........

Sorry about two in a row, just wanted to get rid of the number in my total posts.

Dennis Wilson

Chuck,

The fuel distributor has a cylinder and piston which are made to very close tolerances. If muck has settled out of the old fuel and deposited on the upper wall of the cylnder, it will cause a restriction of the piston movement and result in a lean AF mixture at upper rpms. A possible solution is to add Gumout or Techron liberally and run it at lower rpm's until the muck is gone. A word of caution though. This type of cleaning can loosen the same muck in the tank and ruin the fuel pump. BTDT Best clean the tank and flush all accessable areas before any gas additive cleaners.

Dennis

fst951

Hi Chuck.

Use 1/2 VM&P Naptha and 1/4 mineral spirits and 1/4 Zylol or Xylene. Put about a total of 5 gallons in and make sure all the holes are pluged except one of the top fuel line vents so the VOC's can evaporate. Test the plastic with a couple of capfuls of the mixture since Xylene can affect some plastics. If necessary eliminate the xylene. It worked great in a 1990 of mine. I think that you will be happy with the results.

Good luck.

borland

Chuck,

If you saved some of the dust or particles. You should see how they desolve in a sample bottle of your solvent. You might try taking a flame to them to see if they contain sulfur.

On the plastic tank, I'd try one of the bath room chemicals like "Lime Away" which comes in a plastic container but is acidic. But that wouldn't work on the metal lines.

Chuck Z

I talked with a radiator shop that was recommended to me by three different repair shops that deal exclusively in high end cars and send all of the gas tanks they need cleaned to this shop. The shop told me aceton will get the deposits and varnish like gunk out but they're not sure if it will harm the plastic tank or not. Any thoughts on trying this method or will it destroy the tank or the baffle inside?

borland

Chuck,

Acetone will harm some plastics. It also degrades PVC, which I think is what the gas tank is made from. Also, I don't think it will remove mineral deposits.

kary4th

I didn't use much force at all, and the insert spun like a record. I have no in tank pump (that's another thread), and the filter wasn't attached.

The tank gauge appears to be in fairly good condition. The gasket in the bottom of the tank gauge is 2/3 missing. The residue on the gauge was very sticky at removal. It's now dried and it sounds as if the float is moving freely inside. I imagine if I were to submerge it in gas, the tackiness would return, so I believe I'm going to try to clean it, replace the gasket and use it.

Dennis Wilson

Kary,

Looking at the bottom picture, it appears the bung came out with your strainer. Not good. The bung is the nurled (sp?) piece (collar) that should be permanently mounted in the tank and the strainer should screw out of it. When this happened on my 78 euro, I had to replace the tank.

Dennis