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Leaking exhaust gas - farting noise!

Discussion in 'A4/S4 forum(B5 Chassis)' started by JayB5UK, Apr 13, 2006.

  1. JayB5UK
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    JayB5UK Member

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    Hi, noticed for quite a while now I have a strange exhaust noise under acceleration.

    But the other day I accidentally put my foot down too much before the car was properly warm, and it made a louder kind of noise where exhaust gas was escaping.

    Is it likely to be either a knackered cat, leaking cat to downpipe joint or has anyone experienced loosening manifold / turbo studs.

    Car has done 115k

    Any thoughts appreciated.
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  2. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    Drop the turbo, and check teh gasket - these are prone to failure! Also check all other exhaust gaskets.

    RIch
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  3. JayB5UK
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    JayB5UK Member

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    Looks a right bitch to get in there to drop the turbo!
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  4. Soupie69uk
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    Soupie69uk Owner

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    Sometimes the cats actually snap where they bolt on to the turbo check that.

    Can you not get someone to (while the car is cold) cover the exaust pipes while you feel where the fumes are blowing out?
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  5. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    Not so much drop the turbo, but unbolt it and drop it an inch or so to replace the gasket (or atleast check it). Check the more accessible ones first.

    Rich
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  6. JayB5UK
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    JayB5UK Member

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    Yeah OK. Been wanting to de-cat it anyway, but not got around to finding a suitable pipe yet.

    I also meant to say that the noise is worse when cold, I said when I accidentally put my foot down and used the turbo when still cold! Tut Tut - (Is it me or just that dbw cars are so sensitive to right foot movement in the lower gears?) When she's warmed up the noise is almost gone, hinting that the heat expands whatever is loose.

    When I look is it easy to get at the actuator rod, mine was re-mapped almost 2 years ago and feels a bit flat in 3rd and 4th for a 200bhp-ish car.

    I think the standard exhaust makes a strange noise under boost, always has, unless it is the cat dying! Why are there never bargain performance exhasuts on ebay?!?!
    #6

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