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How do i drain the fuel tank on my 2.5 tdi convertible?

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by s31lew, Dec 20, 2010.

  1. s31lew

    s31lew New Member

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    I urgently need to drain the fuel tank on my 2003 2.5 tdi convertible, can anyone advise?
    cant start the car. engine will turn over until the battery dies.
     
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  3. hades-

    hades- Yorkshire & Humber Rep.
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    remove it
    why do you think the tank needs draining ?
    you put petrol in
     
  4. s31lew

    s31lew New Member

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    do you mean remove the tank completely?

    ...Long story mate, basicly, a work colleage asked me if i would be interested in some cheap diesel at 90p per litre. with the fuel prices continuosly going up...and further to go after xmas, I asked if it was ok and legal, he said he used it in his golf tdi with no probs and assured me it was legal. so I thought i'd try a barrel. I put 25 lites in two weeks ago and it ran fine, so last weekend I bought 3x 25l barrels off him....I put 2 barrels in on Sat morning...the car hasnt started since:-(. its now tuesday and I need to get my car running. I want to drain the tank and change the filter and refill with "proper" garage diesel. I cant move the car off the drive and the snow is about 8-9 inches. so the last thing i want to be doing in this weather is lying under my car but i guess thats the price i got to pay for doing such a stupid trick. I called my work colleage on sat and he had the same problem with his, but he managed to get his car coughing & spluttering to his mates garage to sort it. he appologised and said if i drain it back out he'l refund me.
    I since checked on the tinternet and apparently cheap diesel has a lower cetane number. cetane level in diesel is like octane level in petrol. Its the measure of how quick the fuel ignites. modern diesels (especialy VW/Audi) require a higher cetane level.
    I have learnt my lesson but now just want my car back to normal. :-(
     
  5. swarcup

    swarcup Well-Known Member

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    Just a thought, is there an additive that can be added to give it the oomph needed if all that is wrong is the cetane deficiency? it maybe easier than doing what you are about to do
     
  6. adamss24

    adamss24 Well-Known Member

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    Diesel is diesel and by british standard it should have a min of 49 Cetane (or 45 if i am honest with you). If you have issues with starting then most likely your ran your car on summer diesel or Biodiesel wich has gelled somehow. You can try and drain the fuel by fitting a suction pump (a rubber bulb type) to the pump's pick-up under the rear bench (round black cover held with 3 screws in a triangle) or you can undo the collar but most likely it will snap if you use brute force. Taking the tank off is a massive job and not advisable. I would tow the car to a warm garrage, let it sit overnight, get the car started then fill up to the brim with clean witer fuel. Replace the fuel filter as well !
     
  7. s31lew

    s31lew New Member

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    Thats a thought, i'l do a bit of investgating for an additive, thanks
     
    #6 s31lew, Dec 21, 2010
    Last edited: Dec 21, 2010
  8. s31lew

    s31lew New Member

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    the first thing i did was lift the rear bench. there are two covers, one under each seat. I unscrewed both, I could see the tank but there is no access to put in the pump. There is a small black box in the centre, near the seat belt buckles, with wires going into it, is that anything?
     
  9. hades-

    hades- Yorkshire & Humber Rep.
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    on the tank side you need to lift the pump out i dont know where the bolts are iv only ever done the prtrol ones
     
  10. s31lew

    s31lew New Member

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    the pump is not located there on the diesel convertible. I can see the tank but no pump.
     
  11. Turkster

    Turkster Bro.Paul 2.5TDI Quattro Sport

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    cant you just put a pip in it and suck it back out with a drill pump ?
     
  12. s31lew

    s31lew New Member

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    I tried that too, but there is a filter just beyond the filler cap to sop people syphoning out the fuel.
    Getting desporate now. went to halfords today to get a Haynes manual. But they didnt stock the book to cover the 2.5 V6 TDI convertible, typical!
    Is there an Audi expert out there who can please advise? I only want to drain my tank, should be simple surely? where do I locate the fuel pump? where do i locate the fuel lines coming from the tank?
    Ive looked under the rear bench. ive removed the fuel filter, fitted a hose to the fuel line and tried turning the ignition. ive tried putting a hose down the filler cap. If i could just get into the tank with a hose I could pump it out?
     
  13. s31lew

    s31lew New Member

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    ive tried lifting the rear bench hoping to get into the tank to pump it out but cant do it from there. (ive removed the fuel filter ready to replace it) I cant syphon from the filler cap. The engine needs to turn over to activate the fuel pump, this pumps out fuel but also drains the battery.
    some advise would be much appreciated.
     
  14. murran

    murran Active Member

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    is it under a similar cover in the boot? pull the feed pipe off and put your own pipe on, power the in tank pump up separatley. should take minutes for it to empty the tank.
     
  15. s31lew

    s31lew New Member

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    Hi guys, thanks for all your input. Problem solved, at last! :yes:
    There is a cover in the boot, under the mat. I removed it and loosend the large fuel pump collet and inserted a pipe into the tank. I syphoned out the fuel no problem. I refilled the tank with £20 worth diesel from the local Shell garage and I replaced the fuel filter (I filled this with diesel also to prime it). after recharging the battery, the car started after a couple of turns of the key. Hey presto my car is back on the road again. :yellowrs4:
    Lesson learned - DONT PUT CHEAP/POOR QUALITY FUEL IN A MODERN HIGH PERFORMANCE ENGINE. :no:
    not worth trying to save a few quid, it works out more expensive in the long run.

    Glad I dont smoke though, I syphoned 50 litres out with my mouth, lol. :yum::puke:
    Happy New Year to you all.
     
    #14 s31lew, Jan 3, 2011
    Last edited: Jan 3, 2011
  16. BlackQuat

    BlackQuat Well-Known Member
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    When I put petrol in mine, I ran 12v's to the fuel pump, disconnected the fuel line from the filter, put a hose onto it into a container, made the 12 live and let it pump it's self clear.
     

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