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Volvo Penta 4.3 GXi-JF closed cooling draining

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  • Volvo Penta 4.3 GXi-JF closed cooling draining

    Hi. I'm preparing to winterize my boat that has a VP 4.3 GXi-JF engine from 2008. Since the pictures of the manual that came with the boat and actual engine look a bit different I'm hoping to get some help from discussion here.
    To the raw water side I will just hook up a canister of AF on the engine flush port which will run through the impeller housing and pushed through the heat exchanger and manifolds and exhaust. Afterwards probably also drain the impeller tubes and manifolds. Probably also tape the drive intake holes so it wont suck air instead of AF from the flush port. I understand that the power steering cooler will drain itself when the impeller tubes are disconnected since the part is under an angle in the back of the engine, correct?

    Howevever, since the boat is new to me I also want to drain the closed cooling part. Anotherwords, since I don't know the coolant's properties, I will treat the coolant as if it were water. So I need to drain it and replace with proper coolant. The manual only says "Make sure the coolants freeze point is adequate for expected temperatures", nothing about how to perform the procedure.
    So I was thinking to drain the engine block from both sides.
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    On my case, there is a defroster hooked up to the engine so I'll just take the hose of from engine drain and thats that.
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    Now I have heard about cracked intake manifolds, t-stat housings etc etc so there are few candidates but again manual does not say anythinig. So which ones would be the right ones?
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    Then, I understand I also need to drain the fuel pump from coolant, so probably just unhook the lower end of this tube, correct? One tube also runs from the fuel pump into the exhaust manifold, should I also disconnect that one??
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    Since the heat exchanger is lower than the engine block drains it will still hold the old coolant, what would be the hoses to disconnect to get everything out?

    Every bit of info is appreciated, up here some have already reported first snow

  • #2
    Flushing RV AF thru the raw water side is up to you, but its just going in and drained back out

    So far as draining everything it looks like you have it figured out. Some of the plugs like on the circulating water pump should not need to be removed because they would drain when the block drained. The onse close to each other are for adding hoses to a hot water heater. Do remove the large lower circulating water pump hose on the bottom to complete draining.

    Also don't see the need to drain the fuel pump unless you think the lines are clogged. The lines will drain when everything else is drained. Cooled by raw water from the main pump, the raw water is pushed thru the pump and into the exhaust man

    Normal mix is 50/50 and look at the AF being used to determine protection. Unless you flush the block with fresh water you shouldn't have much of a chance to dilute the new AF going in. If concerned use 60/40 mix but suggest not going above that.
    94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
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    07 Seadoo GTX
    Merc Adults Only VP Adults Only
    G-Dad always said "First Liar doesn't stand a chance"


    • #3
      You have a half system. That means the block, heads and intake have glycol in them

      You need to drain the exhaust manifolds and pull the raw water impeller and back-flush the supply hose with AF
      Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

      1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

      Past Boats
      1970 Wooster Hellion - Merc 9.8
      2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
      1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

      What’s behind you doesn’t matter.Enzo Ferrari


      • #4
        Thanks for input. I was planning to substitute the existing coolant with original Volvo green ready mix, that should probably be suitable for keeping the boat outside through wintertime. Even if there will be some of the existing coolant left in the closed system it would mix with the correct coolant and still be ok. And the old coolant that I drain out I will use to flush through the raw water part of the system since it probably has some AF properties left and raw water part will be drained anyway.
        Also planned to take the cap off from the water separator lower part so water would drain out from there also?
        Other thing that I see a lot is that the leg oil will not be renewed in autumn, but it will be just left to drain through the winter and new oil added before the season starts again?


        • #5
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          You could buy an antifreeze tester kit. They are pennies