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2001 S3 Boost Leak

Discussion in 'A3/S3 Forum (8L Chassis)' started by zseth, Jul 23, 2010.

  1. zseth
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    zseth Member

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    [Jul 23, 2010]
    Hey guys, im sure this a common one, but any help will be appreciated, AMK engine:

    For the past few days now my car is suffering from loss of power, in low gears at full throttle there is a loud hissing noise, in high gears at low revs, there is hissing then when i let go of accelerator there is a dumping noise.

    I checked vag com and no DTC's, and physically inspected for any split hoses, im thinking if the BOV is letting off steam too early?

    only tiny split i found was on the breather pipe under inlet manifold shown in pic, could this be the cause?

    [​IMG]

    Is this a good time to do the bypass?

    Any ideas or clues with details will be much appreciated

    Regards,
    #1
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  3. Matt82
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    Matt82 Active Member

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    [Jul 23, 2010]
    cant see the pic but it sounds like the right hose. if its attached to the manifold then it will be exposed to boost pressure so the split will cause a loss

    time to start pulling it apart
    #2
  4. Welly
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    Welly VX220 SC Driver :)

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    [Jul 23, 2010]
    OEM breather and vac hoses are notorious for being grade a rubbish. Remove and replace with silicone.

    Bear in mind that these hoses have been heated and cooled a million times (well, a few at least :)). Any rubber or plastic based materials won't deal well with that.
    #3
  5. zseth
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    zseth Member

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    [Jul 23, 2010]
    where is a good place to source silicone hoses? i take it they need to be like for like?
    #4
  6. Welly
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    Welly VX220 SC Driver :)

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    [Jul 23, 2010]
    Not really, just some generic hose of roughly the same internal diameter of the pipe being removed is normally fine.

    Ebay is normally your best bet.
    #5
  7. Matt82
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    Matt82 Active Member

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    [Jul 23, 2010]
    autoperformance

    3mm id for the vac hoses. not sure what else you have to replace
    #6
  8. sportstractor
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    sportstractor Chugger

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    [Jul 23, 2010]
    you can buy the rubber bend in silicone from DPM. I bought them and they fitted perfectly. the plastic hosing could be replaced with silicone piping, i have a hose and hydraylics centre a mile away where i buy all mine from.
    #7
  9. zseth
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    zseth Member

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    [Jul 23, 2010]
    cheers guys, so that little split in the breather hose as shown in pic will cause mayhem? i hope its a straight fix, you guys can see the pic right?
    #8
  10. zseth
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    zseth Member

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    [Jul 23, 2010]
    its not connected to the manifold from what i can see, but it is a breather hose split at the connector
    #9
  11. Welly
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    Welly VX220 SC Driver :)

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    [Jul 23, 2010]
    Will deffo be an issue then. Does the car idle a bit funny, hunting etc?
    #10
  12. sportstractor
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    sportstractor Chugger

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    [Jul 23, 2010]
    could cause it to be hesitant etc. Can see the pic you stole, yes lol
    #11
  13. zseth
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    zseth Member

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    [Jul 23, 2010]
    oops forgot to mention, BIG THANKS for the pic, it made life easy instead of trying to explain the thingy!

    i might just replace it for an oem part for now as its a weird shape and actually feels like its part plastic where it goes into the u - bend

    it does not really idle poorly but engine does seem louder than usual
    #12
  14. zseth
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    zseth Member

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    [Jul 23, 2010]
    Ok, called audi dealer and the piece costs 57 pounds and has to be ordered from germany arriving in ten days or so. Forge do a silicone replacement for the horse shoe shaped pipe for 20 pounds but mine has split on the other end so might have to stick to OEM, read plenty about it on TT forums and looks like its a common culprit which effects braking as well!

    so will have to put one on order and in meantime see if i can tape it up or cut it short to see if it cures my problem.
    #13
  15. zseth
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    zseth Member

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    [Jul 25, 2010]
    After a Long 2 hours with no tea and plenty of cuts and grazes later, i finally managed to take out the breather pipes, also broke the dipstick holder in the process which was bound to happen!

    Below is where there are splits in the pipes:

    [​IMG]

    can anyone advise if this will be the cause of my boost leak? the noise seems to come from the passenger side when im driving?

    is there samco etc replacements for this? part numbers 06A-133-783-AS and 06A-133-783-AT & 06A-133-789

    thanks
    #14
  16. zseth
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    zseth Member

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    [Jul 26, 2010]
    Quick trip to audi, one dipstick tube, one dipstick, one 06A-133-783-AS and 06A-133-783-AT and one o-ring for £20 pounds all in.

    now just have to countdown the hours to tomorrow when the parts will arrive and get them on and take the car for a test
    #15
  17. zseth
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    zseth Member

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    [Jul 27, 2010]
    All done, will take the car for a spin tomorrow and see what the outcome is, hope its all sorted now,
    #16
  18. s3dave
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    s3dave TFSI Hybrid

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    [Jul 27, 2010]
    hope all is fine mate
    #17
  19. zseth
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    zseth Member

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    [Jul 28, 2010]
    i hoped so too but its not all good!

    car still hisses when in high gears and full throttle, im starting to think it maybe the BOV dumping too quick?

    low rev hissing has gone
    #18
  20. zseth
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    zseth Member

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    [Jul 28, 2010]
    ok.............

    Decided to pop the bonnet again and ponder....

    Having a doubt that the BOV is faulty, i decided to take it off, as it was awkward i undone the jubilee clip from the hose which runs from the BOV past the N249 valve and connects to the BIG turbo metal pipe. There was a tear in the hose under the jubilee clip and a tear along the jubilee clip as well. I cut it back and re-tightened it, took it for a spin and all is SORTED!!!!

    now im thinking what if i just changed that hose in the first place!

    anyhow.... now its sorted and running sweet!

    Job Done (thanks to welly and everyone else) :eek:)
    #19
  21. s3dave
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    s3dave TFSI Hybrid

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    [Jul 28, 2010]
    great well done!
    #20
  22. DJ_Troopa
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    DJ_Troopa K1 Driver

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    [Jul 28, 2010]
    At least you changed the breather hoses anyway as they're prone to splitting. This is why people always say to check around the DV because it's a very common one lol. I'm the opposite to you and found a leak in my breather pipes!
    #21
  23. Welly
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    Welly VX220 SC Driver :)

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    [Jul 28, 2010]
    They're old engines now & rubber perishes. Theres the problem!

    Anyways, glad it's good now, drive it for a few days and see how you get on.

    And enjoy the restored power.... LOL.

    Good work :thumbsup:
    #22
  24. zseth
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    zseth Member

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    [Jul 28, 2010]
    off topic: should i have an uprated DV if i get car remapped?
    #23
  25. Welly
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    Welly VX220 SC Driver :)

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    [Jul 29, 2010]
    That's a bone of contention.... It's not a necessity, no.
    #24
  26. zseth
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    zseth Member

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    [Jul 29, 2010]
    I am suspecting that the DV is dumping too early as when on full throttle especially higher gears, it tends to lose steam too early

    any local members in the east london area willing to lend their DV for a quick run?
    #25
  27. finesse
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    finesse Active Member VCDS Map User

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    [Jul 29, 2010]
    have you checked the health of your dv?
    #26
  28. zseth
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    zseth Member

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    [Jul 29, 2010]
    yes, i done the test and with piston pushed in and finger on top it drops a few mm and stays there until i release finger when it drops back down all the way, im assuming the few mm drop is normal?
    #27
  29. zseth
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    zseth Member

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    [Aug 7, 2010]
    OK..... so i checked for leaks and split hoses again to no avail, still had major power issues which were becoming intermittent and frustrating:

    The G200 sensor was replaced as ESP light kept coming on,

    The Breather tube from the pressure valve to under the manifold was cracked and leaking boost so for now i cut it and re-tightened it till the new one arrives,

    this seems to have cured the problem for now, FINGERS CROSSED!
    #28
  30. zseth
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    zseth Member

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    [Aug 16, 2010]
    UPDATE:

    I can honestly confirm there are no more boost leaks on the car as pretty much every pipe in the pic in earlier post has been changed , i tried a new N75 valve from the stealers which made no difference so i returned it, i then decided to change the 'puck' valve and although the whooshing sound is still there the car has RETURNED to its former glory!!!

    My tuppence: i had loads of vacuum leaks which had to be sorted, the maf read ok on data runs and n75 change made no difference, the new DV seems to hold boost better and the 'whooshing' i believe is the turbo spooling noise that has gone louder due to the n249 bypass (loud dump noise when foot off accelerator as well), the only thing left was the pressure relieve valve aka 'puck' valve or in my terms 'UFO thingy!'

    replacing this seems to have cured the problem, now the car pulls and pulls and pulls in every gear inc 1st and 2nd which seemed to have lost pull since n249 bypass. Im assuming the spring/valve inside had weakened and was giving in too early causing the pressure to drop hence no power.

    Hope this helps and if anyone needs guidance on anything i went through please ask and il be glad to help

    thanks for all the help from you guys on the matter :s3addict:
    Last edited: Aug 16, 2010
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  31. Madeley
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    Madeley Member VCDS Map User

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    [Aug 16, 2010]
    Hi, is the puck the one on the top right of the engine, l may as well change mine l've changed every thing else like you.
    #30
  32. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Aug 16, 2010]
    Good good you found your problem. What was the price of the "puck" valve and did you just change it because you tried everything else or was there anything visually that made you change it.

    Im having problems with boost and its annoying the s**t out of me now.

    Nathan
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  33. zseth
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    zseth Member

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    [Aug 16, 2010]
    yes it is, its the next part in line towards the grill/headlight after the Diverter Valve
    #32
  34. zseth
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    zseth Member

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    [Aug 16, 2010]
    i changed it last but it was the first thing i suspected as the 'whooshing' sound was hollow and sounded like it was coming from a plastic chamber, the minute i was told by audi what it is, i knew it will be the answer (pressure relief valve) it has a spring inside it which i assume lost its tension?

    nothing visual as a tell tale sign, just last option really. think it was 22 pounds inc vat or exc - cant remember as i ended up getting one from breakers
    #33
  35. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Aug 17, 2010]
    Thanks for that info, I remember taking mine off ages ago and seeing the spring inside it and wondering how it actually works. When my turbo is sucking in air, it pretty loud if your going up a hill but it sometimes sounds likes its releasing the air from somewhere or sucking in from somewhere else, not just through the filter, hard to explain lol.

    I think I might try this before I replace anything else.

    Nathan
    #34
  36. zseth
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    zseth Member

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    [Aug 17, 2010]
    did you do the n249 bypass? i only noticed this after the bypass and it could well be the 'turbo winding up' noise which gets louder as well as the DV
    #35
  37. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Aug 17, 2010]
    My turbo has always been a bit loud because I have a pretty big Jetex cone but it sometimes sounds like it not sucking through just the turbo. But ye, after I did the bypass the car run really good for about 3 miles then blow a turbo hose off then its never ran as good when I put it back on. I dont think the problem is the bypass but the bypass has exaggerated a problem I already had maybe.

    Havent had the time to have a proper look over the engine bay and used my boost leak tester I made yet. My car is really heavy on fuel too right now. But hopefully my boost leak tester finds a leak, if not il replace that "puck" valve you have talked about then maybe my lambda sensor as it does richen up enough under higher load I think.

    Nathan
    #36
  38. Nilz
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    Nilz Defo worth the wait :)

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    [Oct 12, 2010]
    Hey, just ressurecting an old thread, if you look in the pic with all the pipes, can someone just advise if the 06A-133-789 pipe is just a small individual pipe, if so, can I just replace this with a piece of silicon, also can anyone advise on the size of the pipe that I would need, finally, is it just a pull off and push on job on this pipe??

    I have checked on mine and its split in exactly the same place, we have checked all the other pipes and they all seem to be ok, so im hoping this one pipe will sort it, also I notice that there is no clamp on it where the split is, is there meant to be one or not?

    Any urgent responses will be much appreciated.

    Thanks
    Nilz

    BTW its a 210bhp 2002 AMK Engine.
    #37

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