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MTU 12v183 overheat. Final issue, still need help

Discussion in 'Engines' started by CTdave, Aug 7, 2018.

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  1. CTdave, Aug 7, 2018
    #1
    CTdave

    CTdave Senior Member

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    Greenwich CT/ Stuart FL
    i started this new thread so nothing gets confused. Thanks to all who’ve helped so far and here is where I’m at.
    Port side is all good now. Bad gauge or sender so I’m looking for the square type of VDO gauges with senders, 100 to 250 degree scale. If you know where to find the old style square gauge and
    The big problem still exists on the starboard side. Running at 225 degrees. Here’s what’s been done:
    Sea strainers taken apart and cleaned. Water gushes in when sea cock opened.
    New hose from strainer to pump.
    New circulating pump.
    Took apart raw water pump, bronze impeller and everything looks good.
    New thermostats.
    Salt/barnacle dissolving potion pumped through heat exchanger (I have to ask mechanic if they flushed the whole engine, I’m not sure).
    I finally took the kids and friends out for our first ride of the season and winter storage applications are already coming out. I just went slow to a local island and sat for the day.

    If anyone can think of anything else that could be the problem, I might be able to salvage my depression and get the family out on our yearly Block Is. Montauk etc. I’ve spent thousands so far and still have the temp issue. The reading of 225 came from both the mechanical gauge on engine and temp laser gun.

    Thanks for any/all suggestions!
  2. Capt Ralph, Aug 7, 2018
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    I still do not see the inter-cooler noted as serviced or replaced.
    It is in the raw water path.

    Nor dump cans inspected.
  3. Capt J, Aug 7, 2018
    #3
    Capt J

    Capt J Senior Member

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    I honestly cannot see running one of those engines up to 225F where no internal permanent damage has not been done to the engine. Try changing the impellor, a friend had this issue a month ago and impeller looked perfect, but turns out was turning on the shaft. I've had this issue with an air leak on the suction side of the raw water pump. I've also had this issue with zinc blockage in a fuel cooler (restricting waterflow to other area's of the engine past it) and also in the risers. What changed from when it didn't overheat and when it did instantly start overheating? How quick does it start to overheat? With or without a load?
  4. johnjen50, Aug 7, 2018
    #4
    johnjen50

    johnjen50 New Member

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    Also I didn’t see where you said the flow out the exhaust was good. It must not have been if there still was pink in the raw water system. If that flow isn’t good I’d start at the shower heads and work my way backward through the coolers.
  5. Capt Fred, Aug 8, 2018
    #5
    Capt Fred

    Capt Fred Senior Member

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    Plus 1 on the exhaust elbow, impeller inter-cooler and heat exchanger.
  6. Capt Ralph, Aug 8, 2018
    #6
    Capt Ralph

    Capt Ralph Senior Member

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    Pink in the exhaust? Or rust red??????
  7. Jorge Lang, Aug 9, 2018
    #7
    Jorge Lang

    Jorge Lang Senior Member

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    See if the amount of water exiting the exhaust outlet is similar on both sides. There could be clogged holes in the mixer which is holding back some of the water. Also, are you bypassing any water before going to the exhaust? Blue silicon hose is a shade of red, Pink?? Waiting to hear the answer on this one.
  8. CTdave, Aug 9, 2018
    #8
    CTdave

    CTdave Senior Member

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    Water pumping out the exhaust the same as the other side now.
    This engine apparently wasn’t pumping raw water because of an air locked raw water pump. We found a crack/dry rotted intake hose right before where it clamps onto the pump. So, new hose, new circulating pump impeller, thermostats. The raw water bronze impeller looked perfect.
    It heats up slowly. It did heat up quickly before all the above was done.
    It had been running fine last fall but I do recall the last few times that we had gone out, it was getting warmer than the other side by 15 degrees. I thought it could have been crap in the intake or strainer but forgot about that over the winter.
    The idea of a blockage somewhere in the circulating lines must be it, risers or somewhere else.
    Last edited: Aug 9, 2018
  9. CTdave, Aug 9, 2018
    #9
    CTdave

    CTdave Senior Member

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    Just to clarify, the pink antifreeze in the hose between the sea strainer and pump was winterizing fluid. The mechanical raw water pump Wasn’t pulling water because of the bad hose. The hose had a small crack in it just before the clamps that hold it onto the pump.
    There has to be an internal blockage as some of you guys suggest. I did have new risers installed two years ago so I’m thinking the blockage must be somewhere else like you guys suggeststed.
    Last edited: Aug 9, 2018
  10. Jorge Lang, Aug 10, 2018
    #10
    Jorge Lang

    Jorge Lang Senior Member

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    Living in South Florida, I had no idea about that winterizing stuff you Northeners do. Now I know about pink boat fluid.
  11. Capt J, Aug 10, 2018
    #11
    Capt J

    Capt J Senior Member

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    It's just potable antifreeze. You can find it at an RV store. Once I had to find 120 gallons of the stuff in South Florida during the summer time to winterize a 140' fresh water system that was being shipped on a freighter. That was a REAL chore. I also once winterized the fresh water system on a 32' searay with Vodka and pink food coloring because I couldn't get any pink antifreeze. LOLOLOL
  12. CTdave, Aug 22, 2018
    #12
    CTdave

    CTdave Senior Member

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    Well, it wasn't a smoking jin, more like buckshot. Lots of little things but it's confirmed. The mechanical raw water pump lost it's prime due to a cracked hose, Impellers were "ok" nut it was time but the big smoking gun was found today, The gaskets between the plates in the heat exchanger were shot, leaking so coolant was being lost & went out with the raw. The leak in the left inboard side is coming from what I hear so the big manifold has to be machined because of fairly heavy corrosion. Yay! Maybe we'll get one fall trip up to the CT river or even Block might be nice in the fall. Thanks for everyone.s input and your time figuring out suggestions, you're all the best & you certainly "Know Big Boats:!

    My fuel tanks are still full so I guess I could look at it as I saved a few thousand there!
    Thanks,
    David