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Leaking exhaust manifold flange

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  • Leaking exhaust manifold flange


    I have a '67 MKII that is essentially stock in it's configuration.

    The other day I noticed some exhaust noise and last night I traced it to a leaking flange between the exhaust manifold and the head pipe.

    When I got the car I noticed some sort of white stuff packed around this area. I didn't pay much attention at that time, but now I notice that most of that stuff is gone, hence the leak. The exhaust system is new and the bolts won't tighten any more than they are already.

    Is this a common problem?

    What can I do about it?

    Any idea on what the white stuff may have been? Abestos paste?

    Would a header be the way to go?

    Any advice is welcome.


  • #2
    When set up correctly, that flange stays together pretty well, unless the engine is allowed to rock too much (usually worn stabilzer bar bushings) and/or the down pipe to differential side cover bracket is missing/broken.

    Check those. Fix what's wrong and then take the downpipe off of the manifold, clean both well and reassemble. Make sure the flange on the down pipe hasn't been distorted.

    The substance was probably some form of exhaust paste. Not a bad idea on this particular joint.
    The more I know about Minis, the more I know I don't know about Minis.


    • #3
      I had recently replaced those stabilized bushings as they were rather worn so that probably was a contributing factor.

      Thanks Chuck.



      • #4
        I took the exhaust apart today, the down pipe was a little far away from the manifold so I moved it as close as I could and re-assembled with some goop for sealing exhaust systems.

        Question, is the manifold supposed to have a smaller diameter tube that fits into the widened portion of the head pipe? If so looks like mine is gone and this would account for all the goop on there previously.

        Is it just supposed to be the flange on the manifold and the flange on the down pipe connected by the clamp?



        • #5
          Two flanges and a clamp, thank you BMC! I cut an o ring from the mesh supplied with the "Muffler Repair Kit" to reinforce the goop. Seemed to help. The last pipe I disconnected had the bolts tack welded to one half of the clamp. Good idea as there is one less wrench involved. Don


          • #6
            There is a slight taper to the bottom of the exhaust manifold that fits into the open face of the downpipe.

            Make sure ALL the exhaust mounts are loose when you clamp the pipe to the manifold. There should be NO tension at that joint.
            The more I know about Minis, the more I know I don't know about Minis.


            • #7
              Very slight indeed, the repair made it better but I still hear a little exhaust escaping there. I suspect I will be making this repair again in the near future.

              What if a welded a pipe inside the downpipe that fit inside the manifold? There would be a little extra backpressue I am guessing bit it should all but eliminate the leak.

              I will have to think on it for a bit.