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  1. #1

    Default 6BT5.9M2 Running Hot

    I have noticed over the last couple of months that the temperature of one of my engines has slowly been getting hotter under load. The engine will run fine up to around 2000rpm with a minor temp rise from 75 C, but rises up to a temp alarm if I exceed these revs for about 10 minutes. I have also noticed that the water overflow tank is slowly getting lower.
    I have rebuilt the water pump, changed the thermostat and radiator cap, and cleaned the heat exchanges with no difference noted.

    Open to suggestions of what to do next?

  2. #2
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    4,632

    Default Re: 6BT5.9M2 Running Hot

    Remove the exhaust elbow and check it. Probably clogged up. The water that comes in to cool, must be able to flow out unrestricted.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  3. #3

    Default Re: 6BT5.9M2 Running Hot

    Quote Originally Posted by Docksidemarineservices View Post
    Remove the exhaust elbow and check it. Probably clogged up. The water that comes in to cool, must be able to flow out unrestricted.
    I wish I'd read this 2 months ago!! just pulled mine and could hardly see through the thing, running SWEEEEET now, many thanks.

  4. #4
    Join Date
    Apr 2016
    Location
    barnegat NJ
    Posts
    2,706

    Default Re: 6BT5.9M2 Running Hot

    That thread was almost 7 years old riverbuilder,but it helped non the less, Safe and happy boating!!

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