Click for Cross Click for Abeking Click for Mulder Click for Mag Bay Click for Abeking

Cummins 6.3 with water in engine oil

Discussion in 'Engines' started by Capt Fred, Aug 3, 2020.

You need to be registered and signed in to view this content.
  1. Capt Fred, Aug 3, 2020
    #1
    Capt Fred

    Capt Fred Senior Member

    Joined:
    Jun 22, 2009
    Messages:
    319
    Location:
    Long Beach CA
    Asking for a boat neighbor, She has a Sealine 42 with Cummins 6.7. Last week on her trip to Catalina, she noted her port engine over heating. She shut down the engine and proceeded to Catalina. She returned from Catalina on one engine and found out that the raw water pump had failed. She had it replaced with a new unit. That mechanic identified water in her engine oil, said it came in from the heads and the engine needed to be rebuilt. Another mechanic said the water most likely came in thru the intercooler. My question is does water in the engine oil (salt or fresh) mean a rebuild. What would be the harm of draining, flushing several times, fixing the water entry point and running without a rebuild?
  2. NYCAP123, Aug 3, 2020
    #2
    NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    11,205
    Location:
    Long Island, NY
    She could try, but her odds aren't good, especially with salt. The harm could be a cracked block and a replace instead of a rebuild.
  3. Pascal, Aug 3, 2020
    #3
    Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    8,162
    Location:
    Miami, FL
    Salt is worst obviously. Depends on how much there is and long it s been sitting. They need to replace the oil right away and crank it without starting to circulate the fresh oil

    years ago, i got salt water inside my generator due to a poor installation (no vented loop). Water syphoned in, filled the muffler and backed up in the engine. I noticed right away and was able to immediately drain, filled with diesel, circulate, repeat a couple of times and then again a couple of time with oil. Saved the motor

    in this case the question is to know if it’s coolant or salt. Coolant would be a head gasket or possibly a cracked head. Salt would be intercooler.

    first thing after changing the oil would be to pull the intercooler and pressure test it. I would do that before pulling the head.

    I don’t see how a cracked block would result in salt water in the oil. Coolant yes but not raw water.
  4. NYCAP123, Aug 3, 2020
    #4
    NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    11,205
    Location:
    Long Island, NY
    After salt dries on the cylinder walls and pistons what happens next?
  5. Pascal, Aug 3, 2020
    #5
    Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    8,162
    Location:
    Miami, FL
    That s why flushing with diesel and oil has to be done right away. Usually within 24 hours before corrosion starts. Cranking without starting with diesel helps flush the salt. After 24 hours it’s too late
  6. NYCAP123, Aug 3, 2020
    #6
    NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    11,205
    Location:
    Long Island, NY
    If you read the OP it's well past 24 hours already.
  7. Capt Fred, Aug 3, 2020
    #7
    Capt Fred

    Capt Fred Senior Member

    Joined:
    Jun 22, 2009
    Messages:
    319
    Location:
    Long Beach CA
    Yes well past 24 hours, thanks for your replies.
  8. NYCAP123, Aug 3, 2020
    #8
    NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    11,205
    Location:
    Long Island, NY
    Still remember as a kid when a friend dumped his OB into the bay. Out of the water and into a barrel of oil immediately. No problem. Any time a motor ingests or is submerged in salt water pickling it in oil (or diesel) immediately is a must. Don't suppose that mechanic flooded the motor with oil did he? (would have been good)
  9. Capt J, Aug 3, 2020
    #9
    Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    14,434
    Location:
    Fort Lauderdale
    Most likely a head gasket from the overheating.......did she say exactly how hot it got? You'd have to further diagnose it to see.....could pull the injectors and do a compression test.
  10. Capt Fred, Aug 3, 2020
    #10
    Capt Fred

    Capt Fred Senior Member

    Joined:
    Jun 22, 2009
    Messages:
    319
    Location:
    Long Beach CA
    She is going to try to save the engine. She understand the slim chance of success but what does have to lose. She got a mechanic and got the old oil and filter out and replaced with fresh oil and got the flushing started by running the engine. Will post updates as I get them.
  11. d_meister, Aug 4, 2020
    #11
    d_meister

    d_meister Senior Member

    Joined:
    Mar 4, 2010
    Messages:
    469
    Location:
    La Conner, WA.
  12. rtrafford, Aug 4, 2020
    #12
    rtrafford

    rtrafford Senior Member

    Joined:
    Jul 13, 2019
    Messages:
    1,586
    Location:
    Vero Beach
    Yep, pull the injectors and dump marvelous into each cylinder.
  13. Capt Fred, Aug 4, 2020
    #13
    Capt Fred

    Capt Fred Senior Member

    Joined:
    Jun 22, 2009
    Messages:
    319
    Location:
    Long Beach CA
    It actually starts quickly, sound great and no sheen on the water or increased smoke. So promising.
  14. Capt J, Aug 4, 2020
    #14
    Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    14,434
    Location:
    Fort Lauderdale
    If the raw water pump is gear driven, perhaps that's how the water got in there......if it ate the shaft bearings......she might get lucky.
  15. Capt Fred, Aug 5, 2020
    #15
    Capt Fred

    Capt Fred Senior Member

    Joined:
    Jun 22, 2009
    Messages:
    319
    Location:
    Long Beach CA
    Capt J, the pumps are gear driven and I thought the same. She had both gear driven raw water pumps replaced. I was telling her to save the old pumps and get them rebuilt but her mechanic told her one pump was too far gone to rebuild?
  16. Capt J, Aug 5, 2020
    #16
    Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    14,434
    Location:
    Fort Lauderdale
    Generally they should leak out the weep holes when they fail and not in the crankcase, but if it severely ate the bearings, it's possible it could fill the crankcase (in a 1 in a 1000 chance). How hot the motor got before shutting it down and the load it had at the time will be the deciding factor.
  17. Capt Fred, Aug 26, 2020
    #17
    Capt Fred

    Capt Fred Senior Member

    Joined:
    Jun 22, 2009
    Messages:
    319
    Location:
    Long Beach CA
    Update: her mechanic found the leak to be at the intercooler seal. That was fixed and flushed again. Now it is a wait and see.