Announcement

Collapse
No announcement yet.

Should I add coolant to overflow container?

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

    Should I add coolant to overflow container?

    So my service manual tells me to warm up engine without filler cap (on heat exchanger) mounted, and then fill to filler neck and reinstall cap. It then says to add coolant to the overflow container.

    Mine doesn’t say add/full but cold/hot.
    It pretty much never goes up more than 1/2 inch, in other words never reaches cold/hot marks. Should I add to it?

    To be clear, I’ve just drained and flushed everything, and now finished adding fluids, but I’m not sure if I should add more to that container (which has a sticker that says “overflow only, do not add” but I’m not sure if it’s different when replacing coolant.

    #2
    Normally, I keep my overflow tank a bit above the cold mark. If the coolant level is below the cold mark, I’ll add whatever it needs after I make sure the heat exchanger is full.
    P/C Pete
    Edmonds Yacht Club (Commodore 1993)
    1988 3818 "GLAUBEN”
    Hino EH700 175 Onan MDKD Genset
    MMSI 367770440

    Comment


      #3
      Thanks. It makes sense to fill it up a bit IMO as well. That way you can see if the color changes, if there are bubbles or any other issue you don’t want.
      I guess the “do not fill” part is for adding coolant, not when actually replacing it. I have a couple of long hoses for the water heater and defroster as well, and they probably take some of the pressure.

      Comment


        #4
        The coolant level in the overflow bottle may increase and decrease with normal engine temperature cycles. In other words: you may see the level increase slightly after the engine has been run up to operating temps but once it completely cools down you may see the level in the overflow bottle has dropped some, this is where the level should line up with the cold marking on the bottle.
        After a complete cooling system flush you may find the need to add some coolant after a few heat cycles.
        Dave
        Edmonds, WA
        "THE FIX"
        '93 2556
        Carbureted 383 Vortec-Bravo II 2.0:1 18 1/4x19 P

        The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
        Misc. projects thread
        https://www.baylinerownersclub.org/f...56-gctid789773

        Comment


          #5
          What Builderdude says.
          Jim Gandee
          1989 3888
          Hino 175's
          Fire Escape
          [email protected]
          Alamitos Bay, SoCal

          Comment


            #6
            Thanks guys!
            But for it to even reach the cold mark, I will have to fill on the actual overflow container, even though it says not to on the actual container. Either fill to “hot” when warm, or just now top of heat exchanger when cold, then fill to cold mark on overflow container?

            Comment


              #7
              Fill to cold mark when cold.
              Dave
              Edmonds, WA
              "THE FIX"
              '93 2556
              Carbureted 383 Vortec-Bravo II 2.0:1 18 1/4x19 P

              The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
              Misc. projects thread
              https://www.baylinerownersclub.org/f...56-gctid789773

              Comment


                #8
                it says do not fill as in Do Not Fill It Full. It needs room for expansion.

                Comment


                  #9
                  Yeah, after going back the next day it absolutely makes sense. And yes - after a couple of heat up cycles I needed to add 0.5L to the heat exchanger.
                  The only way there’s ever going to be coolant at the cold mark when cool, is to add at the overflow container.
                  It actually does say “Do not fill. For overflow only”. But I’m not filling it up, just adding till the cold mark. That way it will pull fluids back as the engine cools down, making sure the heat exchanger is always full and protected. Air = rust and contamination.

                  Comment


                    #10
                    The pressure cap on the H/E must be correct for a recovery system. In other words, it must have two sealing surfaces and the valving.

                    As the heat expands the coolant, the over-flow is directed to the recovery reservoir. This is when it will/should reach the "hot" line.

                    As the engine cools down, negative pressure builds within the H/E. This is when the coolant returns from the recovery reservoir, and when it will/should reach the "cold" line.

                    It is imperative that the recovery system tube reaches near the bottom of the reservoir, and that the hose (to/from the H/E) does not breach suction.

                    It's also a good idea to have the reservoir at/near the same elevation as the H/E pressure cap.





                    This is showing a car/truck radiator.
                    The recovery system will be very similar to that of a Marine Closed Cooling system with a Heat Exchanger.

                    The pressure cap will seal in two areas..... one at the very top, and a pressure relief seal within the neck.
                    It will also have a one-way valve that allows for the coolant return.





                    In answer to your original question.... add coolant (if need be) when the engine is cold and bring it to the cold line.
                    If it's too full, extract some!


                    .
                    Rick E. Gresham, Oregon
                    2850 Bounty Sedan Flybridge model
                    Twin 280 HP 5.7's w/ Closed Cooling
                    Volvo Penta DuoProp Drives
                    Kohler 4 CZ Gen Set

                    Comment


                      #11
                      It seems like (at least now in cold winter weather) that I don't reach correct operating temperature, well in my short 20-minutes trips anyways... The coolant doesn't seem to go over the cold mark, but does seem to decrease a bit after each run. This means that I'm at least sure that the cap seals so there's negative pressure when it cools down. I did open it a bit too early once, and got a mean hiss.
                      Could it be that the cap isn't opening up correctly when hot? There's some rust on the cap, and the black paint is peeling, should it be replaced?

                      My setup isn't like the one in the photo above, the overflow hose is attached to the bottom of the tank, so it should fill/drain from the bottom. The hose is without kinks.

                      Comment


                        #12
                        ...............
                        Originally posted by DIYglenn View Post
                        It seems like (at least now in cold winter weather) that I don't reach correct operating temperature, well in my short 20-minutes trips anyways..
                        Your engine's thermostat will/should determine engine operating temperature.

                        . The coolant doesn't seem to go over the cold mark,
                        If the engine can reach operating temperature, that may be a good indicator that your heat exchanger and seawater pump are doing their job very well.

                        but does seem to decrease a bit after each run.
                        A good Closed Cooling system will be like the Stock Market...... Zero Sum Gain.
                        In other words, as the engine completes each hot/cold cycle, you should see the recovery reservoir's coolant level consistently return to the "Cold" line.


                        This means that I'm at least sure that the cap seals so there's negative pressure when it cools down.
                        Yes, the negative pressure (caused by contracting coolant) is what pulls the coolant from the recovery reservoir back into the heat exchanger... but only if the cap and the return line are sealing properly.

                        I did open it a bit too early once, and got a mean hiss.
                        Could it be that the cap isn't opening up correctly when hot?
                        You will not want to open the pressure cap while the coolant is hot.

                        Doing so would put you at risk of a burn and it will disrupt the balance between the H/E and the recovery reservoir.
                        The balance will be regained after a few hot/cold cycles.


                        There's some rust on the cap, and the black paint is peeling, should it be replaced?
                        Your call. If it functions, I'd run it.

                        My setup isn't like the one in the photo above, the overflow hose is attached to the bottom of the tank, so it should fill/drain from the bottom. The hose is without kinks.
                        Do you mean at the bottom of the recovery reservoir?
                        If so, you'll see them either way.





                        The style where the coolant enters from the top must have an internal dip tube.


                        Rick E. Gresham, Oregon
                        2850 Bounty Sedan Flybridge model
                        Twin 280 HP 5.7's w/ Closed Cooling
                        Volvo Penta DuoProp Drives
                        Kohler 4 CZ Gen Set

                        Comment


                          #13
                          Originally posted by 2850Bounty View Post
                          ...............
                          The last one pictured actually pulls from the bottom of the tank, you can barely see the connection at the bottom left. The outlet at the top is a vent as the cap is somewhat sealed with no dip tube.
                          Same one I have.
                          Dave
                          Edmonds, WA
                          "THE FIX"
                          '93 2556
                          Carbureted 383 Vortec-Bravo II 2.0:1 18 1/4x19 P

                          The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                          Misc. projects thread
                          https://www.baylinerownersclub.org/f...56-gctid789773

                          Comment


                            #14
                            Is there a maximum length for the hose between the HE and the reservoir bottle? I have bought a reservoir, but the only logical place seems to be on the transom. There was no reservoir with the boat, nor any unexplained screw holes. About 3 ft of hose will cover the distance.

                            Comment


                            • builderdude
                              builderdude commented
                              Editing a comment
                              3’ will be fine👍🏼

                            #15
                            Originally posted by Metrodriver View Post
                            Is there a maximum length for the hose between the HE and the reservoir bottle? I have bought a reservoir, but the only logical place seems to be on the transom. There was no reservoir with the boat, nor any unexplained screw holes. About 3 ft of hose will cover the distance.
                            Once the hose becomes filled with coolant, the distance shouldn't make any difference.

                            It's important that there be no air leaks within that circuit. One small air leak will kill the siphon.



                            Originally posted by builderdude View Post
                            The last one pictured actually pulls from the bottom of the tank, you can barely see the connection at the bottom left. The outlet at the top is a vent as the cap is somewhat sealed with no dip tube.
                            Same one I have.
                            Dang it, Dave....... I have no good excuse for that!

                            I meant to post a pic of one like this, where the hose connection leads to an internal dip tube.


                            Rick E. Gresham, Oregon
                            2850 Bounty Sedan Flybridge model
                            Twin 280 HP 5.7's w/ Closed Cooling
                            Volvo Penta DuoProp Drives
                            Kohler 4 CZ Gen Set

                            Comment


                            • Metrodriver
                              Metrodriver commented
                              Editing a comment
                              I have that one, recommended by Dave.
                          Working...
                          X