Announcement

Collapse
No announcement yet.

Changing antifreeze on Mercruiser 5.0L with FWC-gctid406901

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Changing antifreeze on Mercruiser 5.0L with FWC-gctid406901

    Hi all,

    I need to change the antifreeze. My manual says to have it done by a mechanic and gives no instructions.

    Looking at the water flow diagram it looks like I can remove the hose from the water pump to drain the coolant?

    Do I refill through the heat exchanger? I know the system capacity is 20 qts of the orange AF but is it mixed 50/50 like a car radiator?

    Any advice/tips will be appreciated.

    Thanks.
    Bob
    "Easy Living"
    2007 Discovery 246, 5.0L MPI, CC, B3
    Boating on the Rappahannock River, Virginia

    #2
    When you buy AF the mixing ratio will be listed on the back 80% AF and 20% distilled water is the strongest you want to use.

    Ken
    300SD all options sold.

    Comment


      #3
      I suggest you do some WWW surfing. Many answers to your question.

      Vic

      Ft Myers
      Vic Stewart SN
      Past Commander
      Cape Fear Power Squadron
      Ft Myers Power Squadron
      1998 2859 7.4 L/B2
      Raw water cooled

      Comment


        #4
        I use 50/50 mix. So your 20 qt. system, 5 gallons, buy 3, you'll end up with 1 gallon spare 50/50.
        Jeff & Tara (And Ginger too)
        Lake Havasu City, AZ
        |
        Current: 2008 Playcraft 2400 MCM 350 Mag B3
        2000 Bayliner 3388 Cummins 4bta 250s (SOLD 2020)
        2000 Bayliner 2858 MCM 7.4 MPI B3 (SOLD 2018)
        2007 Bayliner 305 MCM twin 350 Mag B3s (SOLD 2012)
        2008 Bayliner 289 MCM 350 Mag Sea Core B3 (SOLD 2009)
        And 12 others...
        In memory of Shadow, the best boat dog ever. Rest in peace, girl. 7-2-10

        Comment


          #5
          I used to mix my own...50/50 anti-freeze to distilled water....now...I have gotten lazy and just use the 50/50 pre-mixed stuff from wallys...just buy and pour...NO mixing
          1997 Bayliner Trophy 2352
          5.7 Mercruiser/Alpha I Gen II /Full Closed Cooling
          San Diego, CA

          HookEmDanO out ......

          the more people I meet the more I love my dogs !

          Comment


            #6
            Vic Stewart wrote:
            I suggest you do some WWW surfing. Many answers to your question.

            Vic

            Ft Myers
            After 20 pages on Google I found many articles on winterizing but none on replacing. Do you have suggestions on how to refill the system?
            Bob
            "Easy Living"
            2007 Discovery 246, 5.0L MPI, CC, B3
            Boating on the Rappahannock River, Virginia

            Comment


              #7
              Thanks Jeff, Ken and hookemdano. I have one question settled.
              Bob
              "Easy Living"
              2007 Discovery 246, 5.0L MPI, CC, B3
              Boating on the Rappahannock River, Virginia

              Comment


                #8
                bob14094 wrote:
                After 20 pages on Google I found many articles on winterizing but none on replacing. Do you have suggestions on how to refill the system?
                Here is what I do, most automotive and boat cooling systems ... hot coolant flows UP the engine, into the TOP of the radiator or side of the heat exchanger, then it gets cooled, flows into the water pump and cooled coolant gets pushed through the lower / middle of the engine.

                Knowing that, what I do is disconnect the upper rad hose at the heat exchanger, block off the heat exchanger, start the engine cold nad let it warm up. When it gets warm the thermostat will open and coolant will start to flow. Because you disconnected the upper rad hose, the coolant will flow into the bildge. As it does the level in the reservoir will drop, simply fill it up. Once clean coolant is coming out of the upper rad hose, you're good to go.

                Now this gets a little more complex if you have a boat with hot water and cabin heat ... the procedure is different. Do you?

                Comment


                  #9
                  makonnen wrote:
                  Here is what I do, most automotive and boat cooling systems ... hot coolant flows UP the engine, into the TOP of the radiator or side of the heat exchanger, then it gets cooled, flows into the water pump and cooled coolant gets pushed through the lower / middle of the engine.

                  Knowing that, what I do is disconnect the upper rad hose at the heat exchanger, block off the heat exchanger, start the engine cold nad let it warm up. When it gets warm the thermostat will open and coolant will start to flow. Because you disconnected the upper rad hose, the coolant will flow into the bildge. As it does the level in the reservoir will drop, simply fill it up. Once clean coolant is coming out of the upper rad hose, you're good to go.

                  Now this gets a little more complex if you have a boat with hot water and cabin heat ... the procedure is different. Do you?
                  Thanks for the information. The boat does not have hot water or cabin heat.
                  Bob
                  "Easy Living"
                  2007 Discovery 246, 5.0L MPI, CC, B3
                  Boating on the Rappahannock River, Virginia

                  Comment


                    #10
                    The main thing when doing this job is to get a much of the air out of the engine as you can, and then to run it long enough with the thermostat open to get all the remaining trapped air out.

                    What I do when I winterize my raw water cooled engine it this:

                    I drain all the water out the block drains and then disconnect the bottom end of the big hose on the circulating pump, that drains the engine well. Then I replace the block drains and re-connect the bottom end of the cir pump hose. Next I disconnect the top end of that hose at the thermo housing. Then I fill the engine up with no tox antifreeze from the top end of that hose till it starts to come out the thermo housing, even if the thermo is closed, the coolant will flow out a bit.

                    Next in your case I'd make sure the heat exchanger is full, and see if you can find a large funnel to put in the neck of the fill point on the exchanger. I'd run the engine with the funnel in the neck of the exchanger, and try to keep it as full of AF as you can, doing this will allow the engine to warm up, the thermostat to open and air to get out of the system. You will see the level rise and fall in the funnel in the neck of the exchanger and the bubbles rise to the top, you need to run it for a while to get all the bubbles out. It works best if you can get the neck of the exchanger as high as possible. Its like re-filling the rad in a car, the challenge is getting all the air out. Keep a close eye on your thermostat, it the temp will start to rise at first and then when it opens, you should see it drop.

                    You are going to waste AF doing this job no matter how careful you are, so if you use regular toxic AF be careful, it's going to be in the bilge, you want to keep the plug in, and turn off the auto bilge switch temporarily so you don't get it all over the place. Then when you are done you can put a big drain under the bilge drain and drain it into that. Or you could use the no tox af that is meant to be used as engine coolant.
                    88 Four Winns 200 Horizon 4.3 OMC
                    98 Jeep Grand Cherokee 4.0/Selectrac
                    07 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

                    Long Island Sound Region

                    Comment


                      #11
                      My last boat came with a fresh water cooling system, but the coolant wasn't so fresh.

                      I drained the heat exchanger. Unhooked the lowest hose and drained that.

                      I then filled it with water and ran it. Drained it again, refilled it, ran it some more.

                      Pretty much the same as a car with alot of crud in the radiator. Keep flushing it until the water runs clear.

                      Then I added 100% coolant since there was still water in there. I added 2 gallons, so it was probably ended up better than 50% (I think my system was 3 gallons)

                      Run it and top off the reservoir as it burps.

                      It's not rocket science, it's just liquid that has anti rust stuff in it.

                      Comment

                      Working...
                      X