Heat exchanger leaking?

Discussion in 'General Maintenance/Repair Questions' started by tony1b2000, Aug 17, 2019.

  1. tony1b2000

    tony1b2000 Member

    139
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    Hello all,

    I have been seeing some staining under my heat exchanger dripping over the alternator etc..
    I am hoping that it is simply the end gasket that needs replacement and not a crack in it. I have to look closer when I run up the RPMs at idle as I don't see any dripping when at idle. The hose clamp is tight and the hose looks fine.

    Is there an easy way to drain these prior to me removing the end caps? Do they have to be bleed out once I replace the end caps. This is the boats 9th season. 496 Mags
    Any other suggestions greatly appreciated!

    20190815_094022.jpg
     
  2. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    It will drain down on its own, change the gaskets, that's it. Start it up
     
  3. juggernaut1

    juggernaut1 Active Member

    877
    Apr 19, 2015
    Perth, Western Australia
    2006 38 Sundancer
    8.1S / ZF 63V Drives
    That end cap looks like it has a larger gap at the bottom which may be the cause of your probs. Remove and replace gaskets and bolt o-rings. Use Mercury/quicksilver perfect seal on the end cap gaskets too.
     
  4. tony1b2000

    tony1b2000 Member

    139
    Oct 10, 2007
    Salem MA
    350 Sundancer 2010
    496 Mag Seacore Mercruiser , Bravo III
    Thanks for all your help. It was a lot easier than I thought. The water was drained when I took the end caps off so no real mess.
    Just an FYI for those doing this: on my unit there is an O ring that is also needed. It was stuck to the old gasket when I removed it.
    If you forget to put back, ( like i did ) water will start seeping out of the bolt!!
    20190824_101005.jpg

    I did have to flush water through the tubes to clean. Can anyone recommend a good device to use to clear the tubes without damaging them?

    Last, the torque spec on mine was 54 inch pounds which I got from Merc over the phone...
     
  5. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    Rydlyme. You can get it on Amazon or even eBay. I had a 5 gallon bottle delivered. Also good for other raw water systems including ac units.

    The other alternative is to take them off and get them to a radiator shop.
     
  6. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Gun cleaning brush and rod work well
     

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