W113 280SL Fuel tank clogged.

[Thierry du Laos]

This week end I expected to start the engine after getting that new (old) car!
I wanted to flush first the gas tank but after refilling, nothing goes out at the drain plug...
Found the in, out and vent connections clogged.
There isalso  a black, smelly mixture in the tank that bloks every holes.
I don't know for how many this car has been standing in New York without running?
I wonder how I can clean the gas tank now?
I think about filling it with thinner or bicarbonat soda!!!!
Anybody's got experience with that trouble?   
I am interested also with details or pictures of the inside of the gas tank!

[66andBlue]

1. Read the "fuel tank tour" by JA17:
http://www.sl113.org/forums/index.php?topic=1712.0;all
2. Read the technical manual: http://www.sl113.org/wiki/Fuel/Tank
3. And if you still have questions, use the search function above and type in "fuel tank" and you will be surprised how much more information you'll get.  

[Thierry du Laos]

So I understand that it is a very common and known problem....! :'(
Thanks I go right away to read all this!

[Thierry du Laos]

I didn't see any answer concerning pouring caustic soda in the tank to make a full clean?
I have a black smelly mixture in the bottom of the tank and I'd like to get rid of it before reinstalling!
Is there any risk to damage protections, flower pot or else?

[Benz Dr.]

Take it to a rad shop and have them clean it. Many of these chemicals can be dangerous to work with. The rad shop should let your gas tank sit in this solution for a couple of days so the old varnish will be removed.

[cruising]

I just finished removing cleaning, coating and attaching my gas tank. She started up and drove beautifully.
Get under the back of the car. You should be looking up at the gas tank. There is a large round screw thing on the belly of the tank. Unscrew that gently put a bucket under the tank for the gas to drain out. Attached to this screw part is the "flower pot". You can see how much gunk is on the screen of the flower pot. Mine was covered in rust so then I knew further action was required. I am sure that this explanation is as clear as mud. If I can do it, so can you!
Good Luck! Have fun! Amy

[ja17]

Good job Amy!


However, depending on how bad your tank a radiator shop can clean it best. If it is not too bad, rubbing alcohol works very well on fuel varnish. Its cheap and east to get.

[Thierry du Laos]

Thanks 66 and Blue,
This summary was very interesting to understand the gas tank design, flower pot mainly.
I've left my tank upside down for drying a few days, and yesterday: shaking time!!! I got a full basket of oily mud out of the refilling pipe.
Now I've pourred some thinner in to get rid of the remainings.
Should be fine after that.
No rust visible or pieces, just dirt, thanks to that oily mud protection...
I'll post pix later.

[66andBlue]

Thierry,
you need to thank Joe Alexander, aka JA17!
Without him here few of us would have a clue about the tank design.

[Thierry du Laos]

So, thank you a lot Joe.

Here are a few pix to add your albums, sorry my camera could get in the tank!
But you'll get a good idea of the condition....
Lets see this evening how the thinner worked in 24 hours?

[w113dude]

Thierry,

I have seen worse fuel tanks, you may be able to clean it at home but a radiator shop will use better suited chemicals to have it flushed out and are not that expensive.
It looks like you may need a new fuel sending unit too.

[ja17]

Hello Thierry,

     Don't waste your thinner. Rubbing alcohol works much better on fuel varnish.

[Thierry du Laos]

I will do that Joe, thanks.
Just started the car yesterday after she stood 2 years outside in the customs' area.
Runs very nice, its a real pleasure to listen to than engine!

[m300cab]

ALSO check the intake screen on the fuel pump
it also get's clogged

[Thierry du Laos]

Hi,
I thank a lot JA17, the rubbing alcohol is the solution to clean the tanks.
Mine is like a new one now .
Thanks a lot...