Hi, this forum has been wonderful over the years helping me keep my 220D as a daily driver (30mpg too, measured over 40K miles). So thanks to you all.

Compared to you folks, I'm a novice, but I did happen on something that may help one or more of you in the future.

My fuel gauge sender came apart in the tank, no problem, I have several parts cars. But the different pieces stirred up rust in the tank before I got to fix the sender. Next time I'll know that when the fuel gauge starts to move rapidly, the little maze at the bottom of the sender is loose and the sender should be pulled at once before it falls apart.

Anyway, I finally got all the pieces out, but my filters kept plugging with rust, at the worst of times - once in snow near Death Valley. I don't have time to pull a tank and get it repaired (they are all rusty to some extent), but what I did solved the problem: tape a magnet to the primary fuel filter, the little clear, screen one. Use clear wrapping tape. You can see the rust build up inside and empty it when needed.

Now, my tank has settled down, with all its rust secure, and the magnet has done the job. But I'm leaving it there.

Hope this helps someone.

Ron

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1971 220D, daily driver, new paint, 142K
1973 220D, low compression
1975 300D, back on the road! 166K
1971 220D, salvage, rear hit, engine excellent
1972 250, bad cam, but runs!
1971 230, engine stuck
1971 220D, low compression, rusty
1976 240D, salvage, engine excellent
1966 230SL, water in oil after rebuild

I love this idea! I'm going to get a magnet and tape it on there soon.

Kurt

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- '79 240D - engine swap complete! Engine broken in! 28-31 mpg! Lovin' the ride!
- '86 190D (W201-126) - 2.5 NA engine, 5 speed, cloth interior, manual climate controls, 33-34 mpg (sold to forum member).

Nice idea. Nice to see a '71 getting 40MPG too.

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1982 300SD

Nice job. Definitely up for the MacGyver award.

Vinegar works great for removing rust in tanks, but you would have to pull it out. First remove fuel traces with thinner. Fill it with vinegar and let it stand for 1 day. Shake some griveway gravel inside to remove the cakey buildup. Rinse with water and then alcohol to remove the water.
I have cleaned some very corroded tanks and it was so easy.

You are probably the only person to ever actually get +5hp from a magnet on the fuel line :p

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

The metal used to make gas tanks is called tern steel in north america, It is steel coated on both sides with lead basically. Probably other propitary metals in the mix as well.

This I mentioned just for the benifit of anyone out there not aware. Starting in the sixties or even a little earlier the thickness was seriously reduced.Cost cutting and replacement business I suppose as their in house cost was around eight dollars to manufacture a cars gas tank.I had heard that price mentioned a few times over the years.

In order to have true rust develop in a tank the original coating must have been sacrificed perhaps by electroylis over time or something. I always caution making sure it is indeed rust before using any strong cleaner that may attack the original coating.

Very old dried gas can look like rust. The poster obviously was capturing iron oxide with his magnet and I think that was an excellent ideal that never occured to me before.

It could perhaps be used as a test to verify if the interior of a gas car has broken down or it is generating something non magnetic. Since the field strength of the magnet is reduced by the filters plastic curved shape in addition to the plastic cartridge wall thickness as well. Getting a really strong modern magnet would be the best ideal. It should capture more iron oxide.

A weak conventional ceramic magnet may or may not be good enough. Some of the newer magntic materials have almost unbelievable strength in their fields. I think it is neoderm or some simular name for the superior magnets.

Maybe all those ebay cars have magnets on their fuel lines ?

Hi, just as an addition to this thread, I've come to the conclusion that the rust grows as sort of icicles in the tank, as I can run my finger down the filler and feel tiny grains coming off. When the fuel sender came apart, I think it stirred up the little grains, knocking them off where they were growing. The magnet got me the time needed for the rust in the tank to settle down again.

I imagine most of the lining on our 40 year old tanks is "used up" and now we're going to always have rust. But maybe with a bit of care, the rust can remain undisturbed in there, until the tank rots through.

It might work to put one of those really strong magnets at the base of the in tank fuel filter, or it could clog worse. All I know is my little magnet is not catching much these days and I'm watching the fuel gauge needle: it'll move rapidly when the float is moving rapidly and that means the sender is coming apart.

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1971 220D, daily driver, new paint, 142K
1973 220D, low compression
1975 300D, back on the road! 166K
1971 220D, salvage, rear hit, engine excellent
1972 250, bad cam, but runs!
1971 230, engine stuck
1971 220D, low compression, rusty
1976 240D, salvage, engine excellent
1966 230SL, water in oil after rebuild

Is this happening regardless of how much fuel is in the tank? Mine typically jumps when it's at R.

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Never be ashamed to ask for help.

1985 300D
1987 300SDL
1970 Jaguar E-Type OTS
2002 Dodge Intrepid (Traded In)
2011 Ford Crown Victoria