Cleaning Poly Gas Tank

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Jeepin' Pete
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Joined: Mon Aug 06, 2018 10:53 am

Cleaning Poly Gas Tank

Post by Jeepin' Pete »

I am in the middle of re-doing my fuel system, and ran into a problem with my original '90 poly fuel tank. I am attaching an aftermarket fuel filter sock in the very bottom of the tank as seen here: http://www.fsjnetwork.com/forum/viewtop ... 35&t=16478
I test fit the sending unit, and when I pulled it out, the mesh on the bottom of the filter pickup had black sludge on it. I want to correctly clean the tank now, before I put everything back together - how should I clean it?

Also, when I was emptying the very last of the gas out, I poured out all I could, and there was still more gas sloshing around that would not come out no matter how I tipped or shook the tank. I was under the impression that these tanks did not have baffles - do they? Why wouldn't everything pour out?
1990 Grand Wagoneer
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Mass
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Re: Cleaning Poly Gas Tank

Post by Mass »

I cleaned mine out a long time ago. I filled it with water and all the gas came to the top. Emptied it then I sloshed a bunch of nuts and bolts around with some purple power/water mix half a dozen times. Used a magnet to get the bolts out along with a rag on a string to get the bulk of the left over water. Let it dry outside.
Just rinse it really good to get all the soap.
Hope this helps.
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SJTD
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Re: Cleaning Poly Gas Tank

Post by SJTD »

My plastic tank had a sleeve inside the the filler neck. It stuck down into the tank at least an inch past the wall which prevented dumping out any liquid. I removed it and left it out to maybe pick up a little capacity.

Get some of the sludge and see what cleaner works on it and do what Mass did.
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tgreese
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Re: Cleaning Poly Gas Tank

Post by tgreese »

Yeah, I'd use soap and water. You can use the magnet on a stick to remove bolts or whatever. I used similar detergent (generic stuff for a power washer) and dry wall screws on my CJ-6 tank - not plastic, but a similar problem. Shake well. Use your shop vac connected to a smaller hose to suck out what water you can reach, then run the shop vac exhaust into the tank for a while to dry it out.
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Stuka
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Re: Cleaning Poly Gas Tank

Post by Stuka »

The inlet tube protrudes about 1/2" into the tank. So even if you hold the tank with the inlet facing down, not all of the fuel will drain out. And where the pickup tube goes you have the same issue. The threaded part protrudes into the tank, so again, not all of the fuel can drain out of it.

As for cleaning it, I also used soap and water, and then let it dry in the sun.
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Topic author
Jeepin' Pete
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Joined: Mon Aug 06, 2018 10:53 am

Re: Cleaning Poly Gas Tank

Post by Jeepin' Pete »

Thanks everyone! I'll give it a shot!
1990 Grand Wagoneer
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rocklaurence
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Re: Cleaning Poly Gas Tank

Post by rocklaurence »

I had the issue on my tank and coldnt get it clean until I pressure washed it. There was a brownish tar in the tank that soap by itself wouldnt break up. I used dish detergent, pressure washer and then vacuumed the remaining water out.

ericthered
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Re: Cleaning Poly Gas Tank

Post by ericthered »

Just did this today on my 1980 Chief that was sitting 10 years.
Poured out all the bad gas still left in the tank into a 5 gallon jerry can. Then used some ZEP cleaner and some white vinegar as my cleaning mix. Then got about 6 feet of steel chain link and dropped in the plastic tank. Sloshed it around the tank letting the chain slide around all the surfaces. Then used the pressure washer and blasted the inside. Then filled with water so it was overflowing for about 5 min. This flushed out all the cleaning and left over varnish. Pulled the chain and washed again then let sit in the sun all day...all good to go!
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