change out the antifreeze in my Mercruiser MAG 496

tricountytrailtricountytrail Member Posts: 182 ✭✭

I need to change out the antifreeze in my Mercruiser MAG 496s (staying with the original Dex-cool antifreeze). New to me boat and want to freshen it up. Is there an easy way to use the extraction pump and pull it out thru one of the lower hoses (which one will get me to the lowest portion of the block)versus draining it into the bilge?


  • rasburyrasbury Member Posts: 8,166 ✭✭✭✭✭
    Watching this...
  • PickleRickPickleRick Member Posts: 3,833 ✭✭✭✭
    edited October 20
    I've always just dumped mine into the bilge.  I do try to catch as much from the heat exchanger in a small bucket but I always spill more than I catch.  

    Not sure about big blocks but small blocks have removable plugs on either side of the block if you really want to make sure she's dry for the full "flush".  

    Clean up is with the trusty shop vac.  Every boat owner needs one.  

    I wait to do my end of season bilge cleaning after I change the engine/drive oils and flush coolant.   It's amazing how clean you can get a bilge with dawn dish soap, soft brush and a shop vac.  It's like a bubble bath but for a big diesels motor.

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