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Gas tank thoughts?


drtidmore

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As my Reatta has led its life in locales where rust is not an issue.  When I pulled my gas tank the other day the lines and the outside of the tank were still pristine with absolutely NO external rust anywhere.  Things were a bit different internally.  I found a build up of rusty particles in the sump area which I cleaned out as I had done 3 years ago at the last pump replacement.  I am blaming that damned ethanol content in our modern gasoline due to its affinity attracting moisture.  The interior area under the sump is still shiny, so the rust is coming from parts of the tank that I can't see. 

 

As I wanted to get the Reatta back on the road, I chose to clean out the tank and install the new pump, but the internal rusting present me with sufficient concern as to contemplate action.  

 

Obviously, a new tank is one option and from what I can gather from reading the various threads here on the forum, there seems to be a consensus that the Dorman is superior that the Spectra.

 

Another option is to clean out the tank, apply a rust convertor to the interior, then use POR15 tank sealer to seal up the interior. This is certainly the lower cost option and given that the OEM tank seems from the discussions to have had superior internal baffling, I sort of hate to toss the original tank for an inferior design if it can be salvaged. 

 

I think I will do the POR15 tank sealer even on the new tank as it specifically states that it is now formulated to withstand modern ethanol blends.

 

So, the question, given the excellent exterior condition, should I go with the later option or am I deluding myself that such is even a viable option and should just go with the new tank.  

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I don't know the level of interior rust but it is hard to beat the oem from a quality standpoint. I thought the tanks were terne coated from the factory, but could be wrong about that. I guess the question is if the tank is the source, or something else, perhaps the filler tube if not from the fueling itself. I guess I would keep the original and coat it but JMO.

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I should have stated that I was considering the "kit" version for all the obvious reasons.  At first I was thinking about using a rust converter, but after learning more about the kit, I see that the POR-15 tank kit is all inclusive as to what is needed.  In watching the videos, the use of chain or a handful of nuts and bolts to agitate the marine cleaner was pointed out as something to consider.  

 

As for finding ethanol free gas, here in the DFW area ALL gas has added ethanol as part of the overall air quality mandates.  I have not seen ethanol free gas here in many years.  I looked just now to see if there are ANY stations even in outlying areas and the nearest would be a 100+ mile round trip, so not really an option. 

 

I do realize that the rusty particulates could well be from gas station tanks, but I tend to buy all my gas at a Costco location that has a MASSIVE turnover of the gas in their tanks due to the demand.   This particular Costco is about 10 years old so it is possible that the rusty particulate I found in the tank is from them.  I did look in the filler tube as well as the in the fuel pump/sender area and there is no rust to be seen in either.  The buildup I found 3 years ago was from ALL the years of driving up to that point, but this latest is 3 years worth so that raised issues.  

 

I did install a new fuel sock on the new Bosch pump (their warranty requires proof of such), but I would have replace the sock regardless.  I replaced the inline filter on the lower firewall 3 years ago, so that likely should be on my list of things to do again even though it only has about 25K miles on it.

 

The biggest downside that I see with the restoration is that it is a week-long process all said and done.  That is acceptable however if the result is as advertised plus the OEM tank is likely superiorly baffled internally, especially since this was a "luxury" car and the sound of sloshing fuel was something that GM would not have allowed.  

Edited by drtidmore (see edit history)
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Already been where you are.......

Helped a friend with his Reatta that was having fuel problems, we pulled the tank and scooped out hands full of the rust colored residue that looked like coffee grounds.

We thought we did a good job cleaning it, installed a new pump and sock.......that lasted about 2 months.  When we pulled it the second time, more coffee grounds and they had clogged the sock and

caused the fuel pump to get noisy.

For those that have not had a Reatta tank out, the chain, rocks or other method is not like it used to be....the Reatta has a plastic molded part that the pump goes into, it appears the idea is when you get low on fuel, it splashes

into this plastic reservoir and because it is maybe 8 inches in diameter this concentrates the fuel for easy pick-up.  However this plastic part interfers with the access to the rest of the tank making the chain or rock rust removal idea a problem

I also think the reason the rust looks like coffee grounds is the tank was probably factory coated, what has happened is a some point water in the fuel has worked it way under the coating....rusting it away from the tank and it breaks down into

coffee ground like consistency.

Either find a good used tank or go new.  Remember the Riviera, Toronado, Eldorado and Seville all used the same tank so we were able to find a good used Eldorado tank at the Pick-n-pull and it is still going.

 

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Not doubting the veracity of the horror story, but if this is an issue, I wonder where the others are hiding? Perhaps this is the tip of the iceberg? I know the fuel lines were changed in 1990 but were there changes to the tank also? It does make me ponder if I should drop my tank and take a look when it comes out for summer. The pump was changed several years ago to a higher flow Walbro and I don't remember any issues at that time, but that was then.

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I looked a little online about fuel tank composition and fuels. It appears GM tanks were coated with a lead/tin mix, inside and out or nickel under the coating or a zinc/tin as lead was phased out. Apparently the government mandated a minimum ten year life. There was also statements that methanol reacted or leached the lead or some other component degrading the coating. Later in the article, methanol and ethanol were used interchangeably  but they vary drastically in the their reactivity, so I am a little skeptical about all of the info. That said, certain formulations of gas dryer products, such as Heet, do contain significant methanol. The general consensus does seem to be that a fuel tank does have a long, but limited lifespan, particularly with oxygenated fuels. Perhaps the local fuel composition may have some bearing and I know some high density areas used MTBE as an oxygenator although I believe that has fallen out of favor due to other concerns? That is all speculation on my part but just a quick search does reveal there may be an issue lurking.

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23 hours ago, HuevosRanchero said:

I've been using the Lucas Ethanol treatment for a while in the older vehicles. They all seem to run smoother with it and I'm not seeing the quick degradation of components like I used to. 

 

 

http://www.fuelsystemguide.com/what-is-the-best-ethanol-fuel-treatment/

I have been putting that into the tank with every fill up for the past 3 years as a way to combat that worst effects of ethanol on rubber parts.

 

On 4/2/2017 at 11:34 PM, 89RedDarkGrey said:

 

Assuming you used THIS SITE, look around- and notice something: airfields and marinas do not use ethanol containing fuel (for obvious reasons).

 

Any of those near by?

Yes, that is the site I used and NONE nearer than 50 miles ONE WAY.  

 

After reading Barney's post, it does raise questions as to the ability to adequately clean and remove all the loose rust in the OEM tank.  My thoughts had been to introduce the loose nuts and bolt thru the filler neck, but if there are additional baffles in the tank, I may still not be able to mechanically agitate the cleaner solution into all areas.  The amount of dark rusty accumulation that I found this time around was about a good cup full which was in line with what I found 3 years ago.  I really don't think the fuel sock was clogged this time but it was discolored from sitting in contact with the accumulated crap.  As for the noise, this particular pump had been whiny from the day I put it in.  If I had not had to drop the tank 3 times on that previous effort looking for a low pressure & bleed down issue (pulsator rubber had been attacked by ethanol and was allowing blow by), I might have yanked it but when I finally got the pressure problem solved with a new pulsator and then discovered that the new pump was whiny, the last thing I really wanted to do was pull the tank a 4th time.  Granted there are worst jobs than pulling the Reatta gas tank, especially once the car is up on jacks and the rear sway bar is out of the way, but still I really did not want to pull it again. 

 

Getting a new Dorman tank and then doing the POR-15 Tank Sealer on it may seem a bit of overkill, but doing so should preclude a repeat of this situation as we all know that ethanol is not going away. 

Edited by drtidmore (see edit history)
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Guest HuevosRanchero

wow that is disheartening that the tank is being attacked internally like that. Afraid of what I'll find if I  ever have to pull mine off. 

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I don't think the issue is as prevelant as some are starting to make this out to be. There are thousands of these cars [Buick, Cadillacs, Olds, Pontiacs] and every so often there is a failure. What probably has happened is that a few tanks have failed due to a crack or improper treating at the factory when made. I think what drtidmore and a couple other are dealing with is a flawed tank that needs to be redone or replaced.

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11 minutes ago, HuevosRanchero said:

wow that is disheartening that the tank is being attacked internally like that. Afraid of what I'll find if I  ever have to pull mine off. 

Since Barney has run into this situation before, it might be common but undiagnosed, however mine did sit, properly stored with minimal gas, treated with fuel stabilizer, for several years and that may have been the catalyst for my situation, but I have to admit I was pretty shocked to find this much new accumulation after only 3 years since I last cleaned the tank thoroughly.  As I had been using the Lucus Ethanol Treatment religiously since I installed that new pump/pulsator 3 years ago, I had hoped that the internal rusting would have been minimized.

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9 minutes ago, 89RedDarkGrey said:

 

No, that's called fortification against an enemy. How are the tank straps? May I suggest- go to your local big store, get a large diameter thin bicycle inner tube, cut to length, slip over the straps. I've seen many tanks retain moisture at the tank/strap interface- and rust badly. This will allow a better grip to conform to the new tank.

As I mentioned, the tank exterior, the straps and the fuel lines are absolutely rust free!  However, I do like your idea of the rubber layer between the tank and the straps as GM did the same between the tank and the body shell.  Encasing the straps in the inner tube does seem to provide a place for moisture to collect, so I think I will just trim the rubber to slightly wider than the strap.

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