M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: Ramblin MAn on August 20, 2009, 10:24:54 AM
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My new to me field car's fuel tank is ate up with rust. It's no wonder the guy I bought it from couldn't get it to run. It's a mess.
A new tank from Advance is only 211 bucks which is a great deal, except for the trouble of removing it. I even have a lift I can use and it looks like a really tough job.
I was looking at possible methods to clean the tank in place and came across the electrolosys method. It looks like it would be persfect but I want to run it by you guys to see if you have any warnings or issues I may have over looked.
It goes like this. First clean out the tank as best as you can. Drain the gas and then wash it out with a garden hos with nozzle to break up any loose rust. Get it rinsed out.
Plug the holes and fill the tank with a one tablespoon per gallon mixture of baking soda and water.
Take a 6 inch piece of rebar and attatch it to an insulated wire and suspend it in the tank. attach the other end of the wire to the positive lead of a 2-10 amp battery charger. Attatch the negative to the tank.
plug in the charger.
the rebar is "sacrificed" and as it corrodes it gives up it's iron ions to displace the oxegen ions causing the rust in the tank. (or so the story goes)
anyway, for something like a gas tank it can take several days of "cooking" and you have to flush and refil the tank once a day and replace the rebar. but in the end the tank is like new and you've only spent ten bucks unless you don't have a battery charger.
I'm just wondering if you guys can think of a problem using this method.
My concern is becaus the tank is grounded to the body that might cause some kind of flow through the body. but since the body is already used as the ground why would it be an issue?
Sure I would rather put in a new tank, but 200 bucks is 200 bucks.
What do you guys think?
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taking out the tank isn't THAT hard... I recently cleaned mine out and it started to rust on the inside again... so you are WAY better off getting a new one (not new used one...)
to take the tank out, you have to remove the drive shaft, heat shields, and rear muffler. (along with the lines that connect to the tank...) you will need a buddy to get the tank back in. And see it as an opportunity to learn more about your car.
If cash is a concern, then i'd consider going by the POR-15 route. about 80$, but no more gas/metal contact (IE, no more rusting...)
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B318m42w has sound advice,
I too had a rusty tank, pulled it , flushed it with a pressure washer and used some stuff from a friend of mine , old can labled "fuel tank sloshing compound"
designed for airplane fuel tanks
I bet that is what por is now
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I'm actually hoping to "learn" as little about this car as possible. I have an 84 e30, 3 e21s, one of which has an m42 in it, a fiero, a mustang convertable and my SAAB daily driver.
But I hear you. I have the interior halfway out removing the 2 years worth of mud dobber nests that are behind every panel. For what this car has been through I am amazed it is in such great shape overal.
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Well the fuel tank is sitting in my back yard "cooking" away. It's pretty cool. Every 4 hours I go out and unplug the battery charger and pull out the rebar and it is COVERED in rust. I wire brush it off, rinse it and put it back in and plug it back in. Tomorrow I will rinse it out and see what it looks like.
For the curious, I have my battery charger set to 6 amps and the meter shows a 3 amp draw.
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for anyone who is interested, I flushed the tank out this morning and WOW! Science is cool!
Lots of rusty water and clumps of rust washed out. The rebar anode I was using looked like a rust covered magnet. I refilled and started her back up for today.
For esentially what amounts to free it's doing a heck of a job. I just need to go get some of that stuff you mix with water to keep metal from flash rusting and rinse out the tank when I'm done.
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Well, I'm satisfied. I didn't let it go to completely clean, but compared to what it was the difference is amazing.
I didn't get the flash rust inhibitor stuff because I remembered that stuff is pretty toxic and I can't empty the tank without getting it all over my shoes. So I just sprayed down the inside of the tank with WD40 and sloshed it around trying to coat all of the surfaces. I'll rinse a quart of fresh gas through it and blow it out before I put it back in.
For anyone on a budget and a few days to wait this was a real money saver. As long as your tank is in generally good shape you will be amazed at the results.