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  1. #1
    Join Date
    Apr 2013
    Location
    Brisbane Australia
    Posts
    15

    Default AQAD40B coolant leaking through coolant filler cap

    Hello, I noticed a few times after a few hours of running at around 2900rpm I get a bit of coolant loss from the coolant filler cap, and after looking at photos and videos of other aqad40b`s it seems just about all of them do this. Would it be viable to add a coolant recovery tank? has anyone done this? ( my engine does not overheat)

    I have also noticed that the engine room temp is pretty warm ( I am located in Australia) I was thinking of adding 2 blowers, 1 blower sucking outside air in towards the air cleaner on the port side, and another blower on the starboard side blowing air out from the engine room, does anyone have any thoughts on this?

    cheers Yobbo

  2. #2
    Join Date
    Dec 2006
    Location
    Palm Beach, FL, USA
    Posts
    281

    Default Re: AQAD40B coolant leaking through coolant filler cap

    First try new cap, they are rated for certain pressure (7lbs?) and will not seal if bad.

    Try running at 3200-3300rpm and see if you lose more coolant. This rpm is when engine starts to see real load and make real heat

    Instead of fans, just install two vents (louvers), orientated slits so one scooping incoming air fwd, one letting hot air out aft? They mount on the engine box side wall. Unless you have flush/sealed deck like they have alot in the pacific to prevent swell from swamping the motor....

  3. #3
    Join Date
    Apr 2013
    Location
    Brisbane Australia
    Posts
    15

    Default Re: AQAD40B coolant leaking through coolant filler cap

    Thanks Stringer_bell, I have brought a new genuine VP cap (30kpa which is 4.3 lbs) I wont get a chance to take the boat out until the new year due to work, and I do have a flush deck that already has louver vents, although the flow of air seems to be restricted as the vents are high on the side and the engine room is below a flush deck, my theory of using twin blowers, one pulling one pushing is to help the air flow in and out of the existing vents

  4. #4
    Join Date
    Dec 2006
    Location
    Palm Beach, FL, USA
    Posts
    281

    Default Re: AQAD40B coolant leaking through coolant filler cap

    Blowers might work. Diesel engines need air, but 40B does not make any crazy HP so it can get by with what you have now. As for recovery tank, I forget if 40B has hose nipple under the heat exchanger cap? If not, you would have to install one, so that when 4.3psi is exceeded, excess coolant will come out thru the nipple/hose and into the tank.

  5. #5

    Default Re: AQAD40B coolant leaking through coolant filler cap

    Quote Originally Posted by Yobbo View Post
    Thanks Stringer_bell, I have brought a new genuine VP cap (30kpa which is 4.3 lbs) I wont get a chance to take the boat out until the new year due to work, and I do have a flush deck that already has louver vents, although the flow of air seems to be restricted as the vents are high on the side and the engine room is below a flush deck, my theory of using twin blowers, one pulling one pushing is to help the air flow in and out of the existing vents
    Did the new cap fix the issue?

  6. #6
    Join Date
    Dec 2015
    Location
    maplevalley WA
    Posts
    3,469

    Default Re: AQAD40B coolant leaking through coolant filler cap

    This thread is almost four years old!
    It takes a nickle to go first class!
    If it aint broke dont fix it!!

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