possible leak in the fuel tank..help needed | FerrariChat
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possible leak in the fuel tank..help needed

Discussion in 'Technical Q&A' started by bikz, Apr 13, 2012.

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  1. bikz

    bikz Formula 3

    Mar 2, 2012
    1,043
    Malaysia
    #1 bikz, Apr 13, 2012
    Last edited: Apr 13, 2012
    heya guys,

    while my car (348TB) is in for its majors, i had requested that they look into the fuel lines because when I pump in a full tank, there has been a serious amount of fuel smell in the cabin....i assumed the piping/clips were the issue.....however the guys just informed me that there is a possibility of the tank having a crack....

    they do not know the exact location yet as the tank hasn't been removed.....so i'm suspecting if it is a leak in the tank, the crack wld be at the top? as only when the tank is full to the brim does it have the fuel smell.....could i be right?

    The mechanic told me that it could be welded, but welding aluminium isn't the best thing to do he also quipped! ....it might crack down the road or something.....how about brazing it? have any of you guys done any of these methods (or something else) before and how were/are the results? plz suggest.....

    any help is greatly appreciated...thanks
     
  2. bikz

    bikz Formula 3

    Mar 2, 2012
    1,043
    Malaysia
    #2 bikz, Apr 13, 2012
    Last edited by a moderator: Sep 7, 2017
    guys, the mechanic sent me this photo to explain why there might be a leak in the tank...
    apparantly the silver paint from the tank as seen has dripped down due to the leak.....
    however i'm still wondering how they know its a crack on the tank as opposed to a possibility of petrol leaking to the side of the tank from maybe a leak at the inlet/outlet pipes/connectors?
    this would also give the same effect in regards to the dripping of the silver paint right as the petrol would be leaking at these points and running down the outer sides of the tank?

    ps: the smell of petrol in the cabin is immediately after pouring petrol (of any amount actually as opposed to my first posting above...i had a rethink on it and realised that most of the time when i poured petrol, i filled it till full so thats what made me think it only happens when its full....actually when any amount of petrol is poured, there is at least a slight vapour smell).....however worst is still after a full tank and by the time its 3/4 tank there is no more petrol vapour smell anywhere.....
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  3. Cribbj

    Cribbj Formula 3
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    #3 Cribbj, Apr 14, 2012
    I would first look to the flexible filling piping for any potential leaks & cracks - also if there are any vent lines or other flexible connections I'd eliminate those too.

    There are machines called smoke testers that are used for checking low pressure systems such as the evap for leaks. Perhaps one of these could be used to isolate your problem.
     
  4. windsock

    windsock Formula 3
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    #4 windsock, Apr 14, 2012
    A qualified shop will have a smoke machine to test cars from evaperative leaks, manifolds and intakes for cracks and leaks. have them pump the fuel tank full of pressurised smoke and inspect for leaks. Cars of this vintage should consider having all the rubber fuel system components replaced.

    Or there is the alternative.
    http://www.komonews.com/news/archive/4157011.html
     
  5. mikeyr

    mikeyr Formula 3

    Jun 17, 2004
    2,154
    Santa Barbara, CA.
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    Mike Rambour
    #5 mikeyr, Apr 14, 2012
    if the welding shop can handle welding on a fuel tank, then don't worry about the welds they will be fine and the tank good as new. Any shop that will have the know how to flush the tank, fill it with inert gas (so it does not go BOOM) will also have a welder with the required skills.

    Welding alu is not rocket science, I actually find it easier than welding steel. That was not always the case, it takes practice to understand the alu weld puddle.
     
  6. fatbillybob

    fatbillybob Two Time F1 World Champ
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    Aug 10, 2002
    29,277
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    #6 fatbillybob, Apr 14, 2012
    do a search for ernies threads on his fuel tank problems and his evap emmissions problems that damged his tank and caused fuel smells
     
  7. ernie

    ernie Two Time F1 World Champ
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    #7 ernie, Apr 14, 2012
  8. ernie

    ernie Two Time F1 World Champ
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    #8 ernie, Apr 14, 2012
    But before you go that far, get the tank smoke tested.

    By the looks of the pic you posted You may have a spot weld that has popped. The trail of silver paint is from the gasoline dissolving the paint, and it running down the side of the tank.
     
  9. bikz

    bikz Formula 3

    Mar 2, 2012
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    #9 bikz, Apr 15, 2012
    thanks guys for all the headsup....

    Ernie, your threads are brilliant......I did find the "348 gas tank removal" (on a google search actually, and that too on another website!!!) before and had assumed that a spot weld had prob popped out.....but your second thread has just made me realise something.......

    now this was happening to my cap....well it was super tight at every refill and considering the cap was super hot as well, i had to pour some water to cool it off, use a towel and use a whole might of strength to open it....however the "whooosh" is something which happens to all the cars right? so i just thought of it like that....and no CEL lights have come up as well....so i have to get the purge valve looked at.....
     
  10. Glassman

    Glassman F1 World Champ
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    #10 Glassman, Apr 15, 2012
    My car always whooshes when the cap comes off.
     
  11. tr0768

    tr0768 Formula Junior

    Oct 28, 2008
    736
    Lake Stevens Washington
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    Howard Musolf
    #11 tr0768, Apr 15, 2012
    My 308 had both tanks leaking. The fuel will drip from under the exterior coating. It turns out the tank does not have any cracks or was it leaking at the rivits.

    The real problem was the prolonged use of ethenol fuel and the corrosion of the bottom of the fuel tank. My tanks were full of pin holes and the pin holes were not repairable. I stripped the tanks to the bare metal, cleaned and lightly polished the bottoms. We then fabricated new bottom skins. We welded the overlayed skins to the bottom of the tanks. We rolled the edges of the skins to run up the sides of the orginal tank about 2 inches

    After we finished welding, we pressure tested the tanks,, then we put gas in the tanks before we reinstalled them. Fuel has a very fine molecular structed and will find the most minute pin hole. This is a very important part of the repair. Its better to find a welding leak now before you reinstall the tanks. We did find a couple of pin holes which we welded. The tanks were reinstalled and no leaks. We also do not use fuel with ethanol, see other posts here regarding this issue.

    I found that due to the several baffels inside Ferrari fuel tanks, it is impossible to use a internal tank sealer.

    Not an inexpensive repair, but far less expensive than new tanks if avaible, or the manufacture of new tanks. On the 308 all rear suspension had to be removed to acces the fuel tanks. Lots of work but without the repair the 308 was just a garage queen.

    Howard Musolf
    1981 308gtsi
    1982 400i Cabriolet
    1988 Lotus Esprit Turbo
    1920'2-30's Indy Cars
    2 many brass era cars
     
  12. ernie

    ernie Two Time F1 World Champ
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    #12 ernie, Apr 15, 2012
    I had that happen before. A couple of years ago I found a bad copy of one of my threads on another site, in some other language. I think I was searching for a cross reference for a part and it popped up in the search.

    Anyhow, now you have access to the original thread. ;) :D
     
  13. bikz

    bikz Formula 3

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    #13 bikz, Apr 22, 2012
    Last edited by a moderator: Sep 7, 2017
    ok i found my leak....it looked like the pressure built up in the tank and as opposed to ernie's imploding tank, mine kind of expanded/"exploded"...there were slight bulges and one pinhole as a result of this pressure build up....this is what i think happened, my car had been sitting idle for about 3 years before i got it....this is another example of why cars should be on the road rather than sitting in garages idle....i suppose the 2 way valve (turn over valve) which releases the built up gases has malfunctioned a bit...i havent gotten to it to check but this is what i think happened...so the pressure built up to a point where it made a pinhole and the leak has been from there....in the pictures, you can actually see the trail of the petrol which had been leaking when the tank was full...the second pix is the hole itself..the last picture is the hole having been welded shut....
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  14. ernie

    ernie Two Time F1 World Champ
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    #14 ernie, Apr 22, 2012
    I'm glad to know you found, and fixed the problem. Thank you for updating us with your results, and posting the nice pictures.
     
  15. bikz

    bikz Formula 3

    Mar 2, 2012
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    #15 bikz, Apr 22, 2012
    however there is another theory by my mechanic...he has also not ruled out on the fact that the hole could be due to vibrations on the tank and the tank having rubbed on some part of the car as the area where the hole was from ( and some other areas as well on the same side) seemed to have had some of the silver paint having rubbed off due to vibrations or something.....any idea? i however think these minor scrapings happened when the tank was removed from the car....plus there were definitely bulges in the tank which has been "hit back" to normal since.......plus i personally think the tank wasn't breathing well and if the car was in use, the fuel being sucked up by the fuel pumps would have prevented this from happening....
     
  16. Cribbj

    Cribbj Formula 3
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    #16 Cribbj, Apr 22, 2012
    I wouldn't rule out the effects ethanol had on your tank either, as mentioned earlier in this thread. Measuring the bottom with an ultrasonic thickness gauge might highlight some future problems.
     
  17. bikz

    bikz Formula 3

    Mar 2, 2012
    1,043
    Malaysia
    #17 bikz, Apr 22, 2012
    where is the ethanol from?
     
  18. ernie

    ernie Two Time F1 World Champ
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    #18 ernie, Apr 22, 2012
    He lives in Malaysia, so I highly doubt there is ethanol added to the fuel.
     
  19. bikz

    bikz Formula 3

    Mar 2, 2012
    1,043
    Malaysia
    #19 bikz, Apr 23, 2012
    thats right....we hv no ethanol added to our petrol!
     

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