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Thread: Fuel leak

  1. #1
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    Fuel leak

    Hopefully someone can help me with this. Whenever I full my tank it leaks, not sure what to look for. It's fine if I don't fill it to the top but I'm guessing it's either a hole in the top of the tank or a fuel line hose. Has anyone else had problem with a gas leak?

  2. #2
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    Check the 3 ingress and egress pipes(tubes) on the right side of the gas tank by the filler pipe. They are known to rust and severely when they do.
    81 Euro undergoing total nut and bolt restoration
    pictures at: flickr.com/photos/bertsphotos

  3. #3
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    rust destroys welded spots of the "neck", where you put the gas pistol in, which is welded to the fuel tank. usual e24, e12, e28 fuel tank problem. pull off the rubber cover, which is around the neck and you will notice the problem. and, as Bert mentioned, check those 3 pipes too
    Last edited by crime; 08-15-2016 at 06:04 PM.

  4. #4
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    Quote Originally Posted by Bert Poliakoff View Post
    Check the 3 ingress and egress pipes(tubes) on the right side of the gas tank by the filler pipe. They are known to rust and severely when they do.
    Quote Originally Posted by crime View Post
    rust destroys welded spots of the "neck", where you put the gas pistol in, is welded to the fuel tank. usual e24, e12, e24 fuel tank problem. pull off the rubber cover, which is around the neck and you will notice the problem. and, as Bert mentioned, check those 3 pipes too
    thanks for the fast reply guys. I'll be sure to check when I get home.

  5. #5
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    And the seal around the pickup, have had to replace mine before. It's on the top of the tank, so more likely to seep when it is full.

    When you say "leak" what do you mean exactly? Is it dripping or do you just smell it?

    '84 Euro 635CSi Polaris/Pacific, for sale (maybe)
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  6. #6
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    Quote Originally Posted by Sprocket View Post
    And the seal around the pickup, have had to replace mine before. It's on the top of the tank, so more likely to seep when it is full.

    When you say "leak" what do you mean exactly? Is it dripping or do you just smell it?
    It does both. It makes a small puddle. I think it happens if I keep pumping gas when it stops.

  7. #7
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    I guess I would suggest not doing that, eh?

    If it is actually dripping, then it is not (or more than) the pre-pump/pickup gasket. I would park it outside until you figure out and fix it.

    Seriously.

    '84 Euro 635CSi Polaris/Pacific, for sale (maybe)
    Home of the Silver Bimmers: '91 M5, '84 Euro E24, "99 E36, "98 E36, '02 E46 xiT (yes, all silver)

  8. #8
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    Quote Originally Posted by Sprocket View Post
    I guess I would suggest not doing that, eh?

    If it is actually dripping, then it is not (or more than) the pre-pump/pickup gasket. I would park it outside until you figure out and fix it.

    Seriously.
    I filled up yesterday and had no problem. Just stopped pumping when the gas pump clicked. If I do It drips and yeah I park my car outside anyways. Looking back I remember it leaked when I jack up the left side of the car. I'll try all the suggestions you guys gave me and knock it out. I'll report back my findings.

  9. #9
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    Install new hoses, it takes about 10 feet
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  10. #10
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    Going to get around to doing this as soon as it gets a bit warmer. Got a new job and currently drive her 80 miles a day and have to fill up every other day and At 16mpg hwy I’m sure the leak is the culprit. I’ve never driven my car more than a few miles so it’s interesting that even at 300k miles+ I rarely have to top up oil/coolant etc and have no other problems other than the UCAB I’ve been putting off replacing and the AC valve..

    Does anyone know where I can source some good hoses? I recall someone saying I need about 2m. Where does one sources hoses of that length? I’m gonna be sure to do it right so I never have to do this job again anytime soon.

  11. #11
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    I haven't dine this yet, but I was thinking about it this spring. I believe that BMW originally installed fabric-covered 6x11mm low-pressure fuel line, but I have a lot of standard BMW high-pressure 8x13 mm fuel injection hose I'll use instead. I know that high-pressure hose is overkill, but it's pretty tolerant of our high alcohol fuel mixtures over here. Any dealer and many US aftermarket parts suppliers (Blunt, Pelican, RockAuto, etc.) can get it for us.
    Last edited by DesktopDave; 01-07-2018 at 10:22 AM.

  12. #12
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    Fabric covered hose is readily available. It is used on older VWs. I have been told to not use it and high pressure hose needs to be used. I have all lines installed with the fabric covered hose and hate to pull it out as it looks good and also retro at the same time. High pressure fi hose should be available at any decent parts store. Changing those hoses over is not a big job and maybe will take a few hours
    81 Euro undergoing total nut and bolt restoration
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  13. #13
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    Quote Originally Posted by Bert Poliakoff View Post
    Fabric covered hose is readily available. It is used on older VWs. I have been told to not use it and high pressure hose needs to be used. I have all lines installed with the fabric covered hose and hate to pull it out as it looks good and also retro at the same time. High pressure fi hose should be available at any decent parts store. Changing those hoses over is not a big job and maybe will take a few hours
    I recall hearing something similar about the braided hose. Thanks. I’ll try grabbing some 6mm, 8mm and 12mm hoses from autozone or oreilly.

  14. #14
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    The seam that goes around the tank can also leak. I had to re weld part of the seam as gas was leaking from there. It only showed up if you filled the tank over 1/2
    81 Euro undergoing total nut and bolt restoration
    pictures at: flickr.com/photos/bertsphotos

  15. #15
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    Quote Originally Posted by Bert Poliakoff View Post
    The seam that goes around the tank can also leak. I had to re weld part of the seam as gas was leaking from there. It only showed up if you filled the tank over 1/2
    Haven’t considered that. I do know my top hose leaks, I’ll need to check the seam when I get under the car. Hopefully it’s not the tank. Mine only leaks when full.

  16. #16
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    D32D33A8-2584-431C-B47E-B3CBBCD325E0.jpg
    Finally getting around to replacing these tomorrow. Does anyone know where these run to or how to replace them? I’m guessing I could access them from under the car?
    Attached Images Attached Images

  17. #17
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    Hi
    The hoses go to a vapour tank in the (trunk) or boot on the right hand side. A hose then goes to a metal hose that runs along the rear bulkhead to the underneath of the car. This is the vent to atmosphere.
    Be careful removing the hoses from the tank as it is very easy to damage the metal pipes in the picture. If you cut the hoses and drop the tank you can inspect the tank and change all the hoses easily.

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