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  1. #1
    Join Date
    Aug 2018
    Location
    Quebec
    Posts
    10

    Default Moomba MAX raptor 400, coolant issue

    It's the end of the season, sadly. I bought my Max like 6 week ago and i had a strange issue with my coolant system. When i first did my 25hr i dropped the oil and changed the gas filtrer as needed and i've checked the prestone level to see where is it and surprise, no prestone in the bowl. there is no leak, the motor is shiny.

    I called Sport Marine and they told me that maybe there were air bubble in the system, so full it back up and now after another 30hr, there is still no prestone in the tank..

    Any idea ? thanx

  2. #2
    Join Date
    May 2018
    Posts
    4,928

    Default

    If you are sure it’s not an external leak, it can only be an internal leak.

    Has it ever overheated?

    Possibly a warped or cracked head, head gasket or cracked intake manifold.

    Being under warranty, I imagine the dealer will do a pressure test on the cooling system to try and identify the source of the leak.

    I would bet it’s a slow external leak that simply gets purged with your bilge water.


    Sent from my iPhone using Tapatalk
    2021 Supra SA 400
    2018 Supra SA 400 (SOLD)
    Michigan

  3. #3
    Join Date
    Aug 2018
    Location
    Quebec
    Posts
    10

    Default

    Quote Originally Posted by larry_arizona View Post
    If you are sure it’s not an external leak, it can only be an internal leak.

    Has it ever overheated?

    Possibly a warped or cracked head, head gasket or cracked intake manifold.

    Being under warranty, I imagine the dealer will do a pressure test on the cooling system to try and identify the source of the leak.

    I would bet it’s a slow external leak that simply gets purged with your bilge water.


    Sent from my iPhone using Tapatalk
    Thanx for the answer, internal leak would be surprising,the boat is brand new with 30h on it. I'll take a closer look next year while the engine is running and try to see for the external leak first... At first view the motor is top clean.

  4. #4
    Join Date
    Oct 2010
    Location
    Lake Wylie NC Area
    Posts
    2,467

    Default

    At the next oil change, take a sample and set it off for a test.

  5. #5
    Join Date
    Apr 2013
    Location
    Knoxville TN
    Posts
    3,078

    Default

    Never looked into a lab for testing. I assume that is where you send it.

    Blackstone Labs - $28 from Google.


    Sent from my iPhone using Tapatalk
    2018 Supra SL400

  6. #6
    Join Date
    May 2018
    Posts
    4,928

    Default Moomba MAX raptor 400, coolant issue

    Used black stone a lot. Great lab, however coolant internal leak is very easy to see in oil, it turns to chocolate milk pretty quick (no pun intended).

    You can have an internal coolant leak that will not mix with oil directly into the combustion chamber and that will cause white smoke and a sweet exhaust scent. Could be difficult to detect on a boat......

    I would agree with the op that it’s not likely a internal issue, but a slow external leak at a hose connection.

    On an all black engine, a slow external leak would be tough to see as the heat of the engine would dry a slow leak quickly.

    Might need to add a UV dye and use a black light while pressure testing the system.

    I am sure your dealer will happily handle this for you under warranty free of charge.


    Sent from my iPhone using Tapatalk
    Last edited by larry_arizona; 10-18-2018 at 05:52 PM.
    2021 Supra SA 400
    2018 Supra SA 400 (SOLD)
    Michigan

  7. #7
    Join Date
    Apr 2013
    Location
    Knoxville TN
    Posts
    3,078

    Default

    I was thinking the same thing when I first read this. Time for someone to get the UV light out.


    Sent from my iPhone using Tapatalk
    2018 Supra SL400

  8. #8
    Join Date
    Oct 2010
    Location
    Lake Wylie NC Area
    Posts
    2,467

    Default

    Yes, an oil analysis would show coolant, if its an internal leak. A large leak will certainly turn the oil into a milkshake, but a small leak will not, but higher levels of coolant could show on a test.

  9. #9
    Join Date
    May 2018
    Posts
    4,928

    Default

    Just noticed my coolant reservoir is low on my 400, it was topped off at 20 hours and is low again at 39 hours.

    Oil is clean and hull dry, obviously a slow leak.

    Curious if OP found source of leak on his raptor 400.


    Sent from my iPhone using Tapatalk
    2021 Supra SA 400
    2018 Supra SA 400 (SOLD)
    Michigan

  10. #10
    Join Date
    Aug 2011
    Posts
    2,522

    Default

    Quote Originally Posted by larry_arizona View Post
    Just noticed my coolant reservoir is low on my 400, it was topped off at 20 hours and is low again at 39 hours.

    Oil is clean and hull dry, obviously a slow leak.

    Curious if OP found source of leak on his raptor 400.


    Sent from my iPhone using Tapatalk
    Check the hoses for leaks, I found mine near the heater pump.
    http://www.instgram.com/jlyons30
    2002 Moomba Mobius LSV - Sold
    2006 Moomba Mobius LSV - Sold
    2017 Moomba Craz - Enzos, Lead

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