Positive Crank Case Pressure

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  • mcandmar
    S2Forum Zealot
    • Apr 2004
    • 5118
    • Country: Ireland

    #1

    Positive Crank Case Pressure

    Curious to hear your thoughts on this. It started very suddenly when out for a drive. First symptom was lots of blue smoke out of the exhaust when sitting at traffic lights, then after further investigation i found my catch tank was being filled with engine oil very quickly. As in its dumping a pint of oil into in within 10-15minutes of driving. Then there is the high crankcase pressure, which explains it puking out the engine oil into the catch tank.

    I suspect it has broken a piston ring as i cant see what else could do this, but curious to hear other suggestions before i take the bottom end apart.

    91CQ20v - Gone to a new home
    93UR-S4 - The Magic Carpet
    94S2Bus - The Emerald Express
  • S2central.net
    Retired OG Mod
    • Jul 2003
    • 16590
    • Country: Northern Ireland

    #2
    Mark - thats mad - never seen that before - quite funny to watch, but not if its your own motor. All you can do first is a compression test I suppose - that will tell you if any piston rings have cracked. Could be nasty if you damage any crankshaft seals as a result of excessive crankcase pressure - unless your catch can pipework is blocked with some gunje ?
    Paul Nugent
    Webmaster http://S2central.net
    Administrator http://S2forum.com

    1994 S2 Coupe ABY - aka Project Lazarus
    2001 A6 allroad 2.5TDi - family tank
    2003 S4 Avant 4.2 V8 - daily burble

    Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

    There are only 10 kinds of people that understand binary - those that do, and those that don't

    Comment

    • mcandmar
      S2Forum Zealot
      • Apr 2004
      • 5118
      • Country: Ireland

      #3
      Yeah pretty much resigned myself to the fact its pooched and took the car off the road. Need to get my compression tester back from David to investigate further, his motor did not sound healthy either last time i seen him
      91CQ20v - Gone to a new home
      93UR-S4 - The Magic Carpet
      94S2Bus - The Emerald Express

      Comment

      • SteveH
        Super Moderator
        • Jul 2003
        • 4460
        • Country: United Kingdom

        #4
        Check your PCV system isn't blocked somewhere. Never seen pressure like that in the valve cover!
        91 Modded 3B
        14 A6 Avant Black Edition

        Comment

        • macspring
          S2Forum Zealot
          • Mar 2005
          • 6371
          • Home: Ireland Current: Wallis & Futuna

          #5
          Will drop it over tomorrow.

          Comment

          • A80Avant
            S2Forum Obsessed
            • Sep 2005
            • 10873
            • Country: Greece

            #6
            Interesting to see what it is. My bet it's to do with piston rings as well or cylinder walls being ovalled

            Comment

            • _ShurikeN
              S2Forum Maniac
              • Mar 2010
              • 733
              • Country: Russian Federation

              #7
              I had an issue with huge oil smoke amount when this happened:


              Comment

              • LSG
                S2Forum Maniac
                • May 2010
                • 897
                • Country: United Kingdom

                #8
                Nice ! What`s the bore like ?

                Comment

                • Error404
                  Super Moderator
                  • Mar 2007
                  • 19789
                  • Country: United Kingdom

                  #9
                  Yer time for a leak down test me thinks
                  Panthero Coupé quattro 20vt
                  Indigo ABY coupé
                  Imola B6 S4 Avant

                  Comment

                  • newsh
                    S2Forum Obsessed
                    • Aug 2003
                    • 16226
                    • Country: United Kingdom

                    #10
                    If you’ve still got the stock PCV system I’d be checking the one-way valve under the inlet manifold. It might be broken or stuck open.

                    S2 Coupe 3B Project


                    Ur quattro restoration

                    S2 Avant

                    Boost is the new rock and roll!
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                    Comment

                    • popdemonic
                      S2Forum Extremist
                      • Dec 2007
                      • 1304
                      • Country: Thailand

                      #11
                      it just got no vacuum from the intake manifold to create a vacuum for positive crankcase pressure.checking the hose and one way valve(greyish/black) under your throttle.




                      one of a few I5 from Asia.

                      Comment

                      • newsh
                        S2Forum Obsessed
                        • Aug 2003
                        • 16226
                        • Country: United Kingdom

                        #12
                        When my one way valve went bad it blew the cam cover gasket out

                        S2 Coupe 3B Project


                        Ur quattro restoration

                        S2 Avant

                        Boost is the new rock and roll!
                        sigpic

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