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  1. #1
    Cadet
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    Default Mercruiser 3.0 L Water in oil

    Hello,
    I just replaced a head gasket on my 3.0. I set the valves, replaced manifold gasket, replaced everything back into original position. Started up engine and was running good. Left the valve cover off to check the valve adjustment and realized after 30-45 seconds water started to come up thru the push rods and onto the rocker arm. Took everything back off and recheck. Everything appears good. Any suggestion why water would be getting in the oil. Thanks.

  2. #2
    Commander zbnutcase's Avatar
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    Default Re: Mercruiser 3.0 L Water in oil

    Freeze crack in block usually, time to start diggin a little deeper!
    You meet the nicest people at the American Legion.
    "maintenance is always cheaper than neglect"
    "certain parts are USCG approved for a REASON"
    "just because it's in the factory service manual, doesn't mean it's correct"

  3. #3
    Moderator Bondo's Avatar
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    Default Re: Mercruiser 3.0 L Water in oil

    Ayuh,... Sure sounds like a Freeze Cracked block to me too...
    Any Grease is Better,..... Than No Grease at All.......

  4. #4
    Petty Officer 1st Class fishinpa's Avatar
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    Default Re: Mercruiser 3.0 L Water in oil

    did any of the cylinder bores show any sign of water ?

    Overheat i suppose ,then changed head gasket...

    It is possible to have a very small crack in a cylinder after an overheat if not found in the other areas of the block.


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  5. #5
    Petty Officer 1st Class lonemust's Avatar
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    Default Re: Mercruiser 3.0 L Water in oil

    Did you make sure the head wasn't warped?

  6. #6
    Cadet
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    Default Re: Mercruiser 3.0 L Water in oil

    I two am going thourgh the same thing... Had head redone and inspected at napa. Prior to finding water is now in the oil. Manual tells me to retighten gasket bolts after 10hrs... But havent even ran it that long.

    No water was getting in with the muffs on but did when i put it in the lake... Was running well but RPM's wouldnt go over 3500

  7. #7
    Moderator Bondo's Avatar
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    Default Re: Mercruiser 3.0 L Water in oil

    Quote Originally Posted by gwpuma View Post
    I two am going thourgh the same thing... Had head redone and inspected at napa. Prior to finding water is now in the oil. Manual tells me to retighten gasket bolts after 10hrs... But havent even ran it that long.

    No water was getting in with the muffs on but did when i put it in the lake... Was running well but RPM's wouldnt go over 3500
    Ayuh,... You've probably got a Freeze Cracked block as well...
    Drain the block, isolate the water passages,+ pressure test with Air,.. about 15psi...
    You'll Hear the leak,... Follow the sound...
    Any Grease is Better,..... Than No Grease at All.......

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