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Blue smoke after decat

Discussion in 'A3/S3 Forum (8L Chassis)' started by Andy91, Sep 23, 2013.

  1. Andy91
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    Andy91 New Member

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    [Sep 23, 2013]
    Hi I have a a3 aum just short of 102,000
    i fitted a 3" downpipe and decat just over a week ago and when I fitted it I had some slight smoke out the tailpipe but not enough to worry but has got slowly worse, and now there is a fair amount of blue smoke and the smell of burning oil, I'm guessing it's the seals on the turbo? And need some help and advice as there were no problems until the decat was fitted ?
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  3. Squirrelofdoom
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    Squirrelofdoom Member

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    [Sep 23, 2013]
    I reckon turbo seals. Basically decreased back pressure from the more open exhaust system puts more strain on the seals, especially if they are old...someone correct me if I'm wrong
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  4. Andy91
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    Andy91 New Member

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    [Sep 23, 2013]
    Yeah I did some searching and that's what I found but was waiting for it to be confirmed, is there anything that can be done or is it time to find a new turbo?
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  5. Andy91
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    Andy91 New Member

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    [Sep 24, 2013]
    Just an update, after yesterday it was chucking out a fair amount of blue smoke , today I took the car to work and left it running for a good hour and there was nothing no smoke what so ever! Which now really confuses me? Could this of been a build up of carbon or something like that?
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  6. S3 Paul
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    S3 Paul Well-Known Member Regional Rep

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    [Sep 24, 2013]
    I had this on my old engine...
    It was a stem seal that had given up ,
    I was told either turbo seals or stem seals...
    Have you fitted a catch can? as the stock breather can spit a little oil back into the intake system... meaning oil vapour will be burnt ,
    The decat and downpipe will probably highlight it with... the reduced back preasure AND no cat to soak up the oily smoke.
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  7. Andy91
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    Andy91 New Member

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    [Sep 24, 2013]
    There's no catch can jut the standard system, just confused how I left my work in quite a big cloud yesterday and today it's fine, is there any tests I can do myself to find what's at fault?
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  8. S3 Paul
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    S3 Paul Well-Known Member Regional Rep

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    [Sep 24, 2013]
    I was once told about a way to test if it was stem seals but im not 100% sure on it,
    It involved accelerating up in one gear towards the red line and allowing it to rev down in gear all the way to idle. then dip the clutch and rev the engine... blue smoke means the stem seals... or so i was told a few years back now.
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  9. Andy91
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    Andy91 New Member

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    [Sep 24, 2013]
    Great thanks, now you mention it I have heard that before so I'll try that on my way home
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