Gas Tank Sealer deterioration

B

Bruce_MO

Well-known member
Just finished my car a few months ago, and now I'm pretty sure the gas tank sealer I used 20 years ago is deteriorating. I started having carb leaks and my engine dying for no apparent reason, and now I realize that the float needle was sticking open or closed. After taking things apart, the carb float and shut-off needle were covered with a very sticky film, as were the top side of the throttle plate and the inside of the intake. Carb cleaner cleans is right off, though.

I hate to pull the tank and have to boil it out and repaint it. Is there a way to fill/rock the car/drain/refill multple times to do this? Should I use gasoline or lacquer thinner? Some other substance to quickly dissolve the sealer?

Any ideas? I'm willing to try something first before pulling the tank.

Thanks
 
I'm afraid your out of luck. I have not read about anything that will readly dissolve old tank lining and not the paint on the out side.

I hope I'm wrong.

As for the rock idea, you would need to remove the tank and rotate it. Maybe find a way to attach it to a cement mixer and leave it for a few hours?
 
I've also heard of someone attaching a tank to a tractor wheel to rotate it.

The challenge is getting the rocks on the back side of the baffle.

Brent-In_Tenn cleans them out by cutting the tops off, blasting and re-welding the tops back on. Probably the most fail safe.

My old cabriolet looked like it was clean galvanized metal inside, like a galvanized bucket, with no signs of ever having been apart. Probably the original terne coating.
 
I have had this problem as well and feel your pain. For me it was a '54 Chevy so I could just pull the tank. But you are in a different spot. You should pull the tank any direction you go to save the surrounding areas. There are different sealers used. If you remember what you used and possibly have the can still you might be in luck. Look for the solvent used in the mix- i.e. Toluene, Xylol, MEK, etc. This will be the fastest way to see what will cut through it and let it all be pulled out. You will need to gravel, beebee, or nuts and bolts the inside to scrape the remaining bits out. But if you are careful you can do this without ruining the paint.

Don't forget to wash it out good blow dry, shake a little denatured alchohal in it rinse with diesel and re-install with a filter between the tank and carb.


Good Luck,
Tim
 
Are you sure its the sealer and not just old fuel? What type of sealer did you go with? Most of the sealers on the market will peel off in sheets and chunks but if this is just contaminated fuel I would think a good rinsing with some fresh fuel might do the trick.
 
I agree that it might be bad fuel. A year ago I drained the tank on a 20 year old fuel injected car that had sat unused for 4 years. Injectors were totally plugged, not even a dribble, I had to disasemble and manually clean them. It worked fine after that.

Money got tight and I had to drop the insurance and did not drive it for 6 months.

Last week I tried to start it and the injectors are plugged again. New fresh fuel from 6 months ago was in the gas tank.

I drained the tank again and some slimmy bad smelling stuff that looked like orange juice came out, it has stringy like solid pieces suspended in the liquid. Smells really strange too.

"Gas" seems to have an ever decreasing shelf life!
 
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Farrell and Benson bring up a good point. Any gas with ethanol has a very short shelf life and turns very sticky when it gets old. I used a screwdriver to stir some paint and cleaned it with old gas with 10% ethanol. The paint cleaned off, but the screwdrive felt like I had just dipped it in honey. Ethanol works good to stick valves on cars that set over the winter also. Luckily I can buy straight gas about 8 miles away, and that's all I use in my small engines and Model A.
 
This brings up the question of to seal or not to seal? I plan on pulling my tank this winter to fix it, its badly rusted.I've been reading a lot about it and a lot of guys swear by the Hirsch products.Whats the general consensus at this time?
 
molasses, thats right,fill the tank with dilluted molasses leave it for a month or so and your tank and /or sheet metal parts will be rust free.
 
RichPA said:
This brings up the question of to seal or not to seal? I plan on pulling my tank this winter to fix it, its badly rusted.I've been reading a lot about it and a lot of guys swear by the Hirsch products.Whats the general consensus at this time?
Click to expand...

And some are swearing because of Hirsch's products!:D Actually, the MSDS sheet for the Hirsch Tank Sealer is the same as Permatex Gasket Sealer. We are getting in tanks that have had this stuff installed in them that have deteriorated and now is plugging the system. We are using a Caustic solution in a vat that is heated to about 175° and we immerse the tank for about 24 hours to disolve it. Caustic will only remove organic items (paint, sealers, old gasoline, etc.) but will do nothing for removing rust. Molasses will do nothing to remove anything organic.


With regard to whether a tank should be sealed or not, I suppose it is all about how you will use the tank afterwards. Our experience finds that in most tanks the rust is not more prevalent in the bottom but actually in the top. All the time I hear guys say you can look down inside their tank and it is clean & shiny inside. When you stick a scope down inside to view the underside of the top, --or cut the tank open where you can see the insides, almost all of the time we will see a brown film of fine rust, ...and usually it is at both ends behind the baffles. If you can remove the rust and then always keep the tank full of fuel so oxygen cannot get to the bare metal to form more rust, then you are probably OK by not using any type of sealer. If you ever leave the tank ½ full, then whatever those vapors are in the fuel mixed with the air cause the tank to rust again almost overnight. Then it is the sloshing motion of the fuel as you are driving that "wash off" the rust sediment from the top of the tank and now it is floating in the fuel.


The 'Catch 22' is I have no idea what the "best" product to use is because I am now hearing even the PVC based products are starting to disolve in today's fuel. The other day we were discussing tanks and how many we have done over the past 4-5 years. I would say a conservative estimate would be well over 100 tanks, ...and I feel confident that over ½ of them had some sort of sealer in them, and the tank had rust AND sealer issues.


One other thought. I don't know how it is elsewhere but around here our fuel comes from a tankyard in Knoxville. According to several different drivers, the fuel all comes out of the same pipe that empties into the tanker. They say that depending on which brand of station they are delivering to determines what they put into the tank. If one brand has an "oxygenated fuel", then they have a special jug of additives they pour into the tank prior to filling the tank with gas. It supposedly mixes going down the road on the way to the station. Now the funny thing is that if they are taking a load of 10,000 gallons of fuel to the station and the station's tank will only hold 9,400 gallons, then they 600 gallons remains in the tanker and new fuel is dumped in on top of that fuel that is headed for a different brand of station. When you ask these guys about the stations that say there is no ethenol in their fuel, they just laugh because they say to their knowledge the fuel all comes from the same tankyard. Kinda makes you wonder what the truth really is!!
 
thinking outside of the box: this is not my idea, one i heard a while back, instead of using rocks, bb's, chains, and most any other thing you can get into the tank. why not use glass?

break up empty soda bottles, put them into the tank then rotate. the galss IMHO would do a lot more 'cutting" of the rust, rocks, bb's woudl just roll over the rust, glass would really do some serious cutting.

may take a little longer getting all the glass out of the tank, however, it would be stopped by an inline filter.

what do you think??
 
Brent: What you're saying about all gas coming out of same pipe. Doesn't say much for being "brand" loyal or all the advertizing money spent promoting one over another, and what gas is NASCAR really running? Just a thought. Igas retailers DIDN"T advertise how much less would a gallon cost at the pump?
Paul in CT
 
Around 25 years ago there was a tank sealer that was not impervious to addatives in the gas; it would desolve and mess up the carburetor first, the throat and intake above the carburetor would look like its coated with tar, run long enough it will get into the engine and do great damage. Ascetone (hope spelling is right) will cut the searler.

Drain all gas, install 3 gallons of Ascetone, rock A side to side, after good sloching, drain out tank. A friend had a 31 Deluxe Phaeton, had sealed the tank as a preventative measure, didn't want to remove the tank, used the above process and was successful . Be careful to keep the Ascetone off yuur painted surfaces.

It ended up with 3 Model A's in Sacramento, Ca. who had this problem; used Ascetone, and the problem was solved.

Ron
 
BRENT in 10-uh-C said:
. . . When you ask these guys about the stations that say there is no ethenol in their fuel, they just laugh because they say to their knowledge the fuel all comes from the same tankyard. Kinda makes you wonder what the truth really is!!
Click to expand...

Here's two ways to test for alcohol. The first one is free, requires a little math, the second link is a test kit, also indicates if the fuel is moisture fouled:

LINK- Determine % of Alcohol

LINK- Test Kit
 
I will never use a sealer again.I had maybe 20 or so tractors and pieces of equipment done over the years,every one is coming apart.In my case I don't believe it is the alcohol,as a local station has been selling it under the name of gasohol since 1980.I never liked it,but it never bothered.They may have the formula down now for the gas we have now,but they had it down for the gas we had in 1990.What will be in the gas in 2015?Some other alphabet soup name for a chemical we can;t pronounce.I cleaned my tanks with a coarse sand and a gallon of acid,strapped to a tractor wheel for a few hours.I mount them so the sand scours the top as it goes around.It takes a while to get it out after,but it gets out the heavy stuff.I don't sweat the powdered rust.I had a real bad tank in my pickup,so I did the tractor and sand thing on it.After 10 years I had about 1/2 inch of fine powder in the sediment bowl.The only reason I opened it up was because the bowl gasket shrunk up and started to leak.The carb would accumulate a little,but before it could ever become a problem I always have to open it up anyway,because the gaskets shrink up and need replacing.The actual supply hole in the carb is up off the bottom just a little to allow for silt buildup.I do use finger screens in the shutoff valves,just to keep the big chunks from getting into the shutoff and scoring it.I never have fuel blockage problems,I always heve to take something apart to fix shrunken gaskets long before the dirt becomes a problem.We have the same gas situation here as Brent described.I have sat in line at the tank farm waiting to get loaded,behind 6 different labeled tank trailers.9000 gallons,with 3 and sometimes 4 compartments,different additives and dyes.I have seen over 7000 gallons of gas dumped in a trailer that still had 1000 gallons of diesel in it.We have no ethanol free gas available here.A website that lists places with ethanol free gas has one place here in N.H.listed.The owner has no clue why it is listed.He says if he has ethanol free fuel it is news to him.He has never owned a computer,never will,and can't figure out how he wound up listed.There are some stations that are trying to get it to sell for inland marine use.There were some places that had it near the coast but I have no idea if they still do.
 
Thanks for the great feedback. My only concern is how much metal will be left after an abrasive chemical cleaning. This tank has lots of rust in it. I flushed it out several times but it still clogs the in line filter and fills the sediment bowl.On his website Hirsch seems pretty confidant about his sealer even with all the ethanol but who knows what fuel will have in it down the road.I think I'll take my chances without it. Thanks again, i am always amazed how much info you guys provide.
 
I used lacquer thinner. Then put in fresh gas. The carb was locked up, but cleaned up. There is a thread on black stuff in the gas tank months back that covers what I experienced. Bob
 
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