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Registered User
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Confused about cleaning fuel tank
I tried searching old threads for fuel tank cleaning methods and I couldn't find much info.
my tank doesn't look too terrible, some dark goop on the tank walls, some rusty flakes etc. It looks very solid with no rust through. Some people say just use hot soapy water, (I don't think that would do much to clean out the caked on grunge) others say to send it out to radiator shop and boil it out and others say not to boil it as it will damage the plastic swirl pot. I've used ON-OFF marine cleaner on stainless steel diesel tanks in the past and it made the grungy old tank shine like new but I'm worried that this very caustic acidic cleaner will damage the swirl pot. I dumped all the old fuel and sprayed it with pressurized water which seemed to remove most of the solid stuff, rust flakes etc. what should I do next? Is there any problem cutting a small access hole in top of tank so you can fit your hand inside the tank to clean it out. Then cover the hole with a plastic screw on access plate. ![]() |
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Registered
Join Date: Oct 2008
Location: Nash County, NC.
Posts: 8,516
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If you pull the tank, take in to a radiator shop. Have them dip it in the tank and there is a green seal they put inside to seal the metal from rust.
Very nice jobs that I ve seen. Bruce |
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Registered User
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Thanks Bruce, it won't damage the swirl pot?
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AutoBahned
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yes, it will destroy the swirl pot (at least the ones on early cars)
some also report issues with Et-OH fuel mixes and the sealant |
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Registered
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the last radiator shop i wnet to wanted $280 to "boil it out" another $180 to steam it out. i piled a bunch of aquarium gravel and a gal. of carburetor cleaner. did a whole lot of shaking then a lot more, and then even more time trying to get the last of the gravel out (never do that again). i used a hot water pressure washer/w degreaser, used acetone to desiccate, and finished with lacquer thinner. it came out looking new (67 912 tank) i was amazed since every radiator shop told me that it was full of rust and needed their attention (not so it just looked like rust). i also scrapped of the outer material and had it blasted and powder coated. nest step is Stone Guard....
hey, did i destroy the "swirl pot"? what is that thing anyway? |
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Registered User
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The swirl pot is a small plastic pot at the bottom of the fuel tank. It's used on cars with CIS injection system. The swirl pots prevent air bubbles from entering the fuel injection system. That's why I'm so confused about the cleaning and resealing process. I don't want to melt the plastic parts and i don't want to clog the pot up with the wrong sealer. I'm beginning to think these tanks are not repairable.
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Registered
Join Date: May 2011
Posts: 7,245
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I had a similar situation when I reawakened my 79 SC from a 16 year hibernation. My 50,000 mile car, that I owned since 1079 ran perfectly before being put to sleep. At wake up call the tank outlet and inlet, the tank mesh filter, and the fuel level sender unit had substantial thick and wachsy brown gunk deposits. Plus the fuel pump was frozen. After studying the blogs and posts here I decided not to going through with a tank, out of they car, cleaning procedure. After seenig the inside tank pictures here with the swirl pot I figured most dirt will stay outside the swirl pot anyway. I did not feel like getting an after market tank or pay the price for a factory tank. I decided to run an experiment. I cleaned as much of the gunk out from the tank mesh filter hole and the outlet and inlet tubes as possible. Installed a new tank mesh filter, new rear fuel filter, and a new, cheap $50.00 Walbro fuel pump, that I could replace easily if it clogs up. That alone got the car rolling again and it kept running like new ever since, almost for one year, with the original Walbro pump.
That is my experience.
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79 SC Targa 72 T Targa Sold 68 T Coupe Sold 65 912 Coupe Sold 62 356B Coupe Sold Last edited by porwolf; 02-16-2012 at 06:33 PM.. |
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AutoBahned
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these swirl pot tanks are not repairable by the std. "boil it out" method
if the tank needs a very serious cleaning, then you might have to think creatively (big ultrasonic cleaner?) many tanks do not really need a boil it out type cleaning tho |
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Registered
Join Date: May 2011
Posts: 7,245
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Here a re pictures of the swirl pot. Looking at them may explain a lot.
1973 911-T (CIS) Fuel Tank Exposed
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79 SC Targa 72 T Targa Sold 68 T Coupe Sold 65 912 Coupe Sold 62 356B Coupe Sold |
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Registered
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Resolution?
So what did you do about your fuel tank?
And what started you down this path to check it? Did you have an issue? |
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Registered
Join Date: May 2011
Posts: 7,245
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Quote:
Cleaning a Fuel Tank without damaging Plastic Swirl Pot
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79 SC Targa 72 T Targa Sold 68 T Coupe Sold 65 912 Coupe Sold 62 356B Coupe Sold |
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Registered
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Thanks. Did not see it. I'm not sure I have the same issue as I have run my 1977 throughout the year since I've owned it in 1990. Age does catch up with us all, though...
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Slippery Slope Expert
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I recently went through this scenario, rehabbing an '82 SC that has sat for 15 years and was stored with about 3/4 tank of fuel. The tank was a mess.
After a lot of thought and consulatation I decided to go ahead with the dipping at the shop as a gamble; not a lot to lose as the tank wasn't usable as it was. The swirl pot was NOT the issue. It came through with flying colors as the shop guy assured me it would. (Note that this component is common to about everything with fuel injection, not just to Porsches) What didn't make the cut were the studs that retain the fuel gauge sending unit and the threaded fitting for the fuel return line. These were reduced to uselessness. So it's a used or repro tank for me, when the time comes. Lots of other issues to be dealt with first. |
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Registered
Join Date: Oct 2005
Location: Capistrano Beach, Ca.
Posts: 7,235
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One more issue to consider if your rehab the tank. If you succeed in cleaning the tank and not damaging the swirl pot, as mentioned above, there can be a problem if you decide to have a coating inside the tank to prevent future rust. There was a recent thread where the owner's problem was the coating did not adhere well to the swirl pot material and began to peel off, causing clogging of the fuel outlet. Haven't heard of the solution as yet but it is something to consider after going to all that trouble to have the tank cleaned.
Hopefully, someone can find the thread about this issue and post a link.
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L.J. Recovering Porsche-holic Gave up trying to stay clean Stabilized on a Pelican I.V. drip |
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