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Thread: Excessive Oil Weep

  1. #1
    Member Pokette's Avatar
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    Default Excessive Oil Weep

    My push rod tube seals started weeping at about 500 hours total time. They did not leak or weep before this. I say weep because it is more of a nuisance than a real leak. I do not lose a lot of oil - still normal consumption, but it make a HUGE mess over the bottom of the airplane, and out the cooler doors and onto the right landing gear. I was wondering if anyone else had this problem and if they found anything that stops the seeping?
    Diana Votaw
    N110CV


  2. #2
    Senior Member Pete D's Avatar
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    Default Re: Excessive Oil Weep

    It can be hard to tell if it is the round rubber gaskets on the end of the tubes or the "paper" gasket under the small cast fitting that goes between the pair of tubes for each cylinder and the case. I have found those gaskets leaking on planes with 500+ hours on them. It tends to just get worse and worse but it is a rare find.

    Have you had your cylinders off since the engine was new? All gaskets should be changed if that is the case but maybe some were re-used?
    Pete Dougherty
    R & D Shop Manager
    Cub Crafters Inc

  3. #3
    Member Pokette's Avatar
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    Default Re: Excessive Oil Weep

    Pete;
    Yes, I have had the cylinders off - I received the replacement cylinders from TCM and put them on. All gaskets were changed. I just recently changed out the gaskets on cylinders #2 & #4 and they are still leaking. Any ideas?
    Diana Votaw
    N110CV


  4. #4
    Senior Member Pete D's Avatar
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    Default Re: Excessive Oil Weep

    Someone called me about this. Your mechanic maybe?

    We discussed the following possibilities, some of which it sounds like you have checked already:


    • Leaking "paper" gasket between push rod tube casting and the case (replace gasket)
    • Leaking at the rubber doughnut seal under the spring on the end of the push rod tube (replace seal)
    • Push rod tube casting possibly cracked or has a porous casting (replace casting)
    • Push rod tube casting not flat on the side that mates to the case (lap on a piece of sand paper on a flat surface)
    • It also could be a cylinder base O-ring (requires pulling the cylinder to change)


    The gentleman who called sounded like he expected to be working on it and seemed to be experienced and capable of taking care of it. The only things I have seen are a bad gasket between the push rod tube casting and the case, and possibly a porous casting there. Both were easily fixed, and I have only seen one of each but I don't see a lot of O-200s, we mostly have Carbon Cubs around here these days.
    Pete Dougherty
    R & D Shop Manager
    Cub Crafters Inc

  5. #5
    Member Pokette's Avatar
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    Default Re: Excessive Oil Weep

    Thanks Pete, yes he is very capable. Always looking to see if someone else has the same problem so we are not reinventing the wheel!!
    Diana Votaw
    N110CV


  6. #6
    Member Pokette's Avatar
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    Default Re: Excessive Oil Weep

    Don't know if anyone else has had this problem, but we changed the push rod tube gaskets and that helped some. The main leak was coming from the oil filler tube, where the black rubber clamp is. We replaced the the black rubber section and now no more leak! Way easier than replacing push rod tube gaskets.
    Diana Votaw
    N110CV


  7. #7
    Senior Member Pete D's Avatar
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    Default Re: Excessive Oil Weep

    Glad to hear you got it fixed!
    Pete Dougherty
    R & D Shop Manager
    Cub Crafters Inc

  8. #8
    Member Pokette's Avatar
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    Default Re: Excessive Oil Weep

    Still have some weeping... not as much, but some, bothersome
    Diana Votaw
    N110CV


  9. #9
    Member tautrey's Avatar
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    Default Re: Excessive Oil Weep

    Quote Originally Posted by Pokette View Post
    Still have some weeping... not as much, but some, bothersome
    My O-200a is doing the same thing. I replaced the pushrod tube, and top/bottom pushrod seals, pushrod base housing paper gasket, cylinder base gasket - and it still leaks below the #4 cylinder and the leak collects at the base of the pushrods.

    My next attempt will be to replace the pushrod adapter housing gasket (paper gasket) again and etch the gasket surface to try to get a good seal.

    Thomas Autrey
    KHEG

  10. #10
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    Default Re: Excessive Oil Weep

    Quote Originally Posted by tautrey View Post
    My O-200a is doing the same thing. I replaced the pushrod tube, and top/bottom pushrod seals, pushrod base housing paper gasket, cylinder base gasket - and it still leaks below the #4 cylinder and the leak collects at the base of the pushrods.

    My next attempt will be to replace the pushrod adapter housing gasket (paper gasket) again and etch the gasket surface to try to get a good seal.
    Google real gasket. They make a conversion like the 0-470. I did the conversion on my C170 with C145. The motor was dry always. You have 8 oil leaks now that will never go away

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