Aftermarket Fresh-water Cooling Conversion

Discussion in 'DIY Marinizing' started by JPC, Nov 1, 2005.

  1. JPC
    Joined: Jun 2005
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    Location: Hong Kong

    JPC Junior Member

    I'm checking to see whether anyone has experience/recommendations w/r/t converting a raw-water cooled diesel to fresh-water cooling. I have a sailboat with an older Yanmar 2-cyl which used to be in fresh water and is now in salt (unfortunately, I'm sitting in my office, so don't recall the model#, I think it's the QM15 -in any case, it's 1-2 generations prior to the current and, I believe, never had fresh-water cooling as an option). I'm considering:
    (i) one of the aftermarket kits, (ii) piecing together components myself (ex-auto mechanic, so not so far-fetched), and (iii) shrugging and waiting for the engine to self-destruct. -I'm leaning towards doing it myself, as I'm not sure there's even a kit available, so am interested in any comments on adding water pumps, etc. from someone who's already skinned their knuckles with this sort of project.

    Any comments would be very welcome

    Here are two aftermarket/heat-exchanger companies, both were dead silent on email info requests, and with my time zone, I haven't called them yet:

    1 person likes this.
  2. Carteret
    Joined: Jan 2004
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    Carteret Senior Member

    A trip to a junk yard can find you a power steering bracket to mount your raw water pump. Grainger Industrial (catalog sales) has a really nice bronze oil cooler that will serve as a heat exchanger.
  3. woodboat
    Joined: Nov 2003
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    Location: Baltimore MD, USA

    woodboat Senior Member

  4. JPC
    Joined: Jun 2005
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    Location: Hong Kong

    JPC Junior Member

    Carteret - Woodboat -

    Thanks for the input
    Joined: Oct 2002
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    FAST FRED Senior Member

    Sendure is the classic source for the best in cupro nickel 90/10 heat exchangers.


  6. bpadlows
    Joined: Jan 2006
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    Location: New Jersey

    bpadlows New Member

    Adding fresh water cooling to raw

    Hi JPC,

    I also had an old Yanmar, a YSB-8, from 1977. It was in fresh water until 1995, when it was then moved to salt water. I also wondered if I should do this conversion, but saw that there are so very many RAW water cooled engines like ours which are still running fine after 30 years in salt water. So I decided to leave well enough alone, and save the money & trouble. And guess what? Eleven years after making that decision, the only thing I've ever had to fix on the engine was the exhaust elbow. And that's normal wear & tear for a near-30 year old engine!

    Go with the flow- leave it raw water cooled, it will very likely be fine for many years to come!

    Bob P.
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