Mercruiser 350 Leaking Manifolds and Milky Oil

Discussion in 'Sterndrives' started by Scarab26, Apr 15, 2007.

  1. Scarab26
    Joined: Apr 2007
    Posts: 2
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    Location: Australia

    Scarab26 New Member

    Hi all,

    Can anyone here answer this....can you get milky oil just from a leaking exhaust manifold on the mercruiser?

    I have a leak in one of my manifolds on the left bank and it was quite bad and I am hoping that there is no further damage. The motor was running fine until it started to run a bit rough, of course i whipped the plugs out first and noticed water in all 4 cylinders so it cant really be a blown headgasket.

    the oil isnt milky on the dipstick but it is milky looking down through the oil filler.

    I am waiitng on a new manifild as we speak so i can restart the motor and get the oil changed anf flush it out but mainly just wanted to know if anyone had experienced milky oil with simply a faulty exhaust manifold leaking water into the exhaust ports.

  2. Frosty

    Frosty Previous Member

    Well if youve got water in the cylinders then it will seep through the ring gaps into the sump.

    This mixes with the oil and it goes milky.
  3. Bergalia
    Joined: Aug 2005
    Posts: 2,517
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    Location: NSW Australia

    Bergalia Senior Member

    Mercruiser 350 leaking manifolds

    Does the exhaust manifold have a waterjacket - not too sure of these engines. But a non water-proof seal between manifold and its cooling jacket would give you milky oil. Remove manifold/s clean faces thoroughly and refit after smearing faces and new gasket with vaseline or gasket goo (flexible) and retighten nuts working from centre to edges to ensure no 'curvature' of the faces. Run for an hour or so and then retighten nuts.
  4. crackerjack
    Joined: Feb 2007
    Posts: 29
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    Location: new jersey

    crackerjack Junior Member

    had the same problem. changed the gasket between the manifold and the water resivior and problem solved. hope this helps

  5. Scarab26
    Joined: Apr 2007
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Australia

    Scarab26 New Member

    got the new manifild bolted on and so far so good.

    running smooth and have drained the oil and thrown some new stuff in. will let it flush through and then change oil and filter next week

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