Fuel Tank Interior Cleaning, Looking for a shop to acid/boil in SoCal, SanDiego

[JohnnyC]

Greetings Fellow Pagoder's,  I would like to clean out the interior of my gas tank, which is in very descent condition, but could use a cleaning for piece-of-mind.  I have been reading in the Tech Manual and it seems acid dipping or a boil-out would be what I need.  Does anyone know a place in San Diego or Los Angeles that can give my tank a cleaning?

I have thought about using Diesel Fuel, but that doesn't seem very effective.

Cheers and Thank you,
JohnnyC

[Jordan]

Hello JohnnyC.  I cannot help you with a location for cleaning but just remember that the flower pot in the tank is plastic.  Also keep in mind that if you had a lot of rust in your tank then the wall thickness has been compromised.  How much will depend on how much rust there was but you will not know where it is paper thin and where it is not.  I had so much rust in my tank that it clogged the flower pot and starved the engine when the gas dropped below the upper lip.  I ended up purchasing a new tank and have never had a problem in the 10 years since doing so.

[MikeSimon]

You can tackle the project using cleaning vinegar. But it still may attack the plastic. I don't know. It is a tad time consuming. needs to sit for at least a week.
Another method we use for rusty motorcycle tanks is "molasses". Mix at a 5:1 ratio with water. Also takes time,but works quite well.

[Pawel66]

Perhaps buying a new one is an efficient option to have it clean inside?

[roymil]

I had good luck using Eastman's fuel tank sealer after having the tank professionally boiled out.  I also flushed it extensively and used a bore scope to inspect the interior.   Fortunately I had no leaks other than through the decayed vent lines.  Make sure you use fuel rated rubber lines to replace all of them.  You can also see quite a lot from the top of the tank with the sending unit removed.   Initially my flower pot was a mess since that where debris will naturally settle but it really cleaned up nice.   The sealer kit comes with good instructions and I was very happy with the clean white epoxy-like coating throughout the inside of the tank.  Wear your hazmat gear if you try it yourself since the chemicals are pretty harsh.   It's worth it though if you think through the chemistry of what is happening.  Properly done, it could add many years to the tank life for not a lot of money.  Hope that helps!
Mark

[roymil]

Sorry, I had the name wrong for the tank sealer kit.  It's not Eastman, its Eastwood.  Here's a link to the instructions:  https://www.eastwood.com/gas-tank-sealer-howto-instructions-and-buyers-guide

[mbpaul]

My experiences.  Tried twice to clean my tank and same problems after each.  Engine sputtered and loss of power.  I finally broke down and got a new MB tank.  Difference was unbelievable.   So glad I did it.  You will not regret getting a new tank (except for the price!).

[roymil]

Fair point, when I consider all the time I've put into cleaning up and refurbishing the fuel system vs. what I'm worth as a mechanic / hour (??;-),...maybe a new tank would have been a better route.  But then I would have missed all those fun hours wearing a respirator in the hot Texas sun, followed by multiple investigations and fuel filter replacements.   All said, it was worth it for the satisfaction of doing it myself.   

Also, regardless of which route you take, I cant emphasize enough the need for putting in one of those clear plastic fuel filters just outside the tank so you can easily see the contaminants collect and prevent them from reaching those expensive fuel pumps.  -Mark

[dirkbalter]

Also, regardless of which route you take, I cant emphasize enough the need for putting in one of those clear plastic fuel filters just outside the tank so you can easily see the contaminants collect and prevent them from reaching those expensive fuel pumps.  -Mark

I am looking for one of these but can't find one in the right size, the biggest connection I can find is 3/8 or 9.5mm where as the fuel line to the pump is 12mm ID. What did you use?

[roymil]

Yes, I ran into the same problem and was about to kluge up a solution when I found this kit , including 2 filters, clamps, & hose.   They already worked out a solution to size up the filter fittings by adding an over-sleeve that's just the right size for our larger feed line.  Seems like a fair deal at $29. -Mark

https://mercedessource.com/store/early-fuel-injection-electric-fuel-pump-pre-filter-upgrade-kit

[dirkbalter]

Thanks Mark,
Looks good.
I was worried about restricting the open area to much and causing flow problems. Based on Kents recommendations, I guess that's not an issue.

(John, sorry for hijackings you post)

[Jordan]

Dirk, if you ever go to swap meets there should be plenty of vendors selling those fuel filters, in multiple sizes.  Pre Covid you could get them for a few bucks each.

[mdsalemi]

My experiences.  Tried twice to clean my tank and same problems after each.  Engine sputtered and loss of power.  I finally broke down and got a new MB tank.  Difference was unbelievable.   So glad I did it.  You will not regret getting a new tank (except for the price!).

Couldn’t agree more. I had the same issues about 15 years ago, but thankfully, nobody suggested I try any bizarre concoction to coat the inside of the tank. A trusted Mercedes-Benz mechanic said the only solution is to replace it and you won’t be sorry and he was dead nuts right.

I question the term acid dip here because if I am not mistaken the inside of the tank is galvanized meaning a thin zinc coating on steel. Putting any kind of [low pH] acid, even vinegar, in the tank and letting it sit for a week is guaranteeing you’ll remove all the zinc and just create more problems. While it is doubtful that vinegar or any similar acid will attack the plastic flowerpot it will certainly attack the zinc coating.

It really couldn’t be any easier here. If you have a problem with your fuel tank replace it. Anything else is just a Band-Aid and temporary. Treated properly, your next, new fuel tank will last longer than you will well into the next owner of your car.

[Mike Hughes]

Good advice, all, but I can't help but go back to the opening sentence of the original inquiry:

Greetings Fellow Pagoder's,  I would like to clean out the interior of my gas tank, which is in very descent condition, but could use a cleaning for piece-of-mind. . .

My question for Johnny C is if he is experiencing any particular fuel system problems, debris in or clogged filters, etc., that would lead one to feel the need for a cleaning/replacement beyond a simple flushing with diesel fuel?  If not, then I'm of the mind that "if it ain't broke, don't fix it."

[JohnnyC]

Thank you all for your reply's.  As suggested..., "If it ain't broke, don't fix it," which I somewhat agree.

In conclusion, I will douche with diesel fuel (because the interior isn't all that bad) and install an in-line fuel filter prior to the electric fuel pump inlet. Replace in-tank drain plug/filter screen, seals and repaint. Possibly replace the fuel level sensor while I'm in there.

Thank you again.
Cheers and God Bless,
JohnnyC.

[WRe]

Hi,
here you can find some information about a professional tank renovation: http://www.witti-tanksanierung.de/foren/PeterH.html.
...WRe

[merrill]

hi
i have also used the eastwood kit on my sl and 300d.

the process is fairly straightforward,   i did not notice any damage to the flower pot in either tank,

you must be careful not to accidentally plug any of the lines or the flower pot input hole.  ( i used a variety of thick guitar strings and air to clean out the lines and avoided the base of the flower pot when circulating the sealer.)

[Jordan]

Thank you all for your reply's.  As suggested..., "If it ain't broke, don't fix it," which I somewhat agree.

In conclusion, I will douche with diesel fuel (because the interior isn't all that bad) and install an in-line fuel filter prior to the electric fuel pump inlet. Replace in-tank drain plug/filter screen, seals and repaint. Possibly replace the fuel level sensor while I'm in there.

Thank you again.
Cheers and God Bless,
JohnnyC.

JohnnyC, since your are cleaning the in tank filter you should also clean the fuel pump filter (its in the fuel pump) as well as the fuel filter in the engine bay.  Then you are starting with a clean slate.

[dirkbalter]

John,
in addition to Marcus suggestion, I would also take the cap of the fuel pump of and inspect / clean the impeller chamber. If your tank had debris, it tends to collect and ruin the impeller, especially the aluminum ones. 

[Pinder]

if you really want to clean out the tank (but I think from reading this your tank is pretty good shape so dont do this unless its really clogged up and you need to clean out the flower put linkes) is to cut the top of and get in there by hand then re seal the top. you can boil it etc. but  there is nothing like going in there yourself and scrubbing it spotless.

[Nicolas Aristodemou]

I have tried many remedies to sort various issues with my fuel tank, including pressurizing it with low pressure air to restore a bump in its shape. In the end, having spent a lot of time and money, a new tank was the way forward. All issues instantly resolved.

Nicolas

[Pawel66]

That was my point earlier. Maybe buy a new tank?

[JohnnyC]

Thank you All for your reply's, great suggestions.  I'll do a thorough inspection and see how it all looks inside.  If I choose to replace with aftermarket, I've heard some are better than others.  Anyone have any experiences with replacement fuel tanks. '70 280.

Cheers and Thank you,
JohnnyC.

[Nicolas Aristodemou]

You will find many new tanks for sale on ebay Johnny, depending on your location around 400 euro