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Blowing and vacuum from filler cap?? Wtf

Discussion in 'A3/S3 Forum (8L Chassis)' started by Omniquito, Sep 24, 2012.

  1. Omniquito
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    Omniquito Member

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    Ongoing oil pressure issues bring me to post more and more random observations and puzzling findings...

    Check this one out...

    So I put the car on ramps prior to a bottom end strip in search of the oil pressure holy grail and on tick over I pulled the oil filler cap off... It was hard to remove breather oil all around the cap.

    I couldn't work out if it was a pressure behind it or a vacuum but it seems like it has both!!! WTF

    I put a tescos receipt over the hole, if I place it an inch over the hole it blows the paper away, if I force the paper onto the hole it's sucked down??

    Can anyone explain what the hell is going on please? Lol

    S3, 2000 plate. APY motor
    done 220k
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  2. coatesy
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    coatesy poking badgers with spoons

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    Can you see oil been squirted up in to the top end you should be able to see with the engine running and taking the filler cap off.

    As I said in the othere thread try a new pressure sensor mate there only a few quid from tps or Audi, don't get a ecp or eBay one and sensors are usually gash if there not OEM genuine stuff
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  3. Omniquito
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    Omniquito Member

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    Don't see any oil splashing around really, just vapour...
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  4. jimmcgee
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    jimmcgee Member

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    its your pcv valve , do search for pcv faults
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  5. wesmaster
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    wesmaster Member

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    As above, PCV valve below inlet manifold, changed loads of them.
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  6. Omniquito
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    Omniquito Member

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    Thanks chaps, i thought that was the case but can you help me clear up some confusion though...

    The valve you are on about on mine is a NON spring loaded flap valve, my questions are:

    A) should it be spring loaded?
    B) people keep telling me thats not the pcv and the real pcv is in the oil filter/cooler housing?

    Whats the truth?

    Thanks, Neil
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  7. VAB
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    VAB Member

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    Have a look at the "simply the PCV system & fit a catch can thread - Good description of the PCV valve - The valve links the line between the crankcase breather and the rocker cover breather with an inlet under the manifold. When it malfunctions it causes the issues that you are seeing as it does not allow for the pressure adjust
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  8. Omniquito
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    Omniquito Member

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    Thank you, i read that and wondered why it conflicted with a lot of people telling me it was a simple flap valve and NOT spring loaded and that the proper prv valve is in the filter housing??
    Even the guy at audi said it isnt spring loaded :-/
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