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  1. #1
    imp0ster's Avatar
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    Oil filler cap blowing off

    It only started happening since I overheated and replaced the head gasket. Since then I overheated again(both time my fault forgetting to open the shutoff valve).

    The cap is very tight when screwed on. WTF causes this? Possibly boost building in the crank case?


  2. #2
    Boost addict hotbird's Avatar
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    you have the oem plastic fill cap?

  3. #3
    imp0ster's Avatar
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    yes. 2 of em now the other one unhinged itself and came out from under the engine

  4. #4
    imp0ster's Avatar
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    I should mention the oil is clear and at the same level. It doesn't smell like race fuel. My plugs are unreadable due to the TORCO.

  5. #5
    Mod less, ride more! troyheb's Avatar
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    So the filler cap is blowing off, but the dip stick stays in? That's strange.

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  7. #6
    imp0ster's Avatar
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    Quote Originally Posted by troyheb View Post
    So the filler cap is blowing off, but the dip stick stays in? That's strange.
    SERIOUSLY!!!!!!!!

  8. #7
    Boost addict hotbird's Avatar
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    Way back when I first joined this site everyone said to ditch the plastic filler cap for a alum one that jerry sold.

    Not sure if that's still applies or not. They claimed the cap would come off and all the oil would exit the motor.

    I don't see them in Jerrys store anymore so maybe they did not work out??

  9. #8
    Mod less, ride more! troyheb's Avatar
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    I have never had a problem with the stock cap, but I did have a piston pop out the side of a block a couple of years ago.

  10. #9
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    on earlier 4-tecs there is a valve by the oil filter cap..blow off if memory serves..maybe the source of the pressure build up. does the ski have a wirewound dipstick?

  11. #10
    shrabber's Avatar
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    If you are blowing the oil filler cap specially since it was over heated, sorry to say your getting positive crank case pressure!!! Either your engine breather, our what I suspect is blowby. Compression has got to go up or down

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