Found a loose copper tube in my exhaust manifold

Discussion in 'All Things Boats & Boating' started by Tharayman, Dec 19, 2020.

  1. Tharayman
    Joined: Dec 2020
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    Location: North cape

    Tharayman Junior Member

    Upon changing the headgasket on a Mitsubishi 4D31 I took off the exhaust manifold. Upon doing so I heard a rattling sound in there. Removed the frost plugs(yeahm they are called that when not installed in a block), and saw a piece of loose copper tubing in there. Does anyone want to guess what it is doing in there?

    I did a leak test using acetone, but no leakage into the exhaust side.

    IMG_4292.JPEG
    Best snap I was able to make

    IMG_4291.JPEG

    IMG_4294.JPEG
    The whole thing

    IMG_4222.JPEG IMG_4223.JPEG
    Leak test in progress
     
  2. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    Do any bolts go through the manifold" If so it could have been a sleeve to isolate the bolt from the water and came loose somehow. Just guessing?
     
  3. Tharayman
    Joined: Dec 2020
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    Location: North cape

    Tharayman Junior Member

    Naaah man. Nothon going through it.
     
  4. Eric ruttan
    Joined: Jul 2018
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    Location: usa

    Eric ruttan Senior Member

    in the first pic it looks like the aluminum is cracked and fallen away, reveling it.

    Can you get a sharper shot of the first pic?

    Is it an evdiesel manifold?
     
  5. Tharayman
    Joined: Dec 2020
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    Location: North cape

    Tharayman Junior Member

    Yess. A bit of support sheet or something is cracked in there. But most of it is left.
     
  6. Eric ruttan
    Joined: Jul 2018
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    Location: usa

    Eric ruttan Senior Member

    Why did you remove it?

    Contact evdiesel?

    If the exhaust stays in the exhaust tube, and the water in The jacket, then what could be wrong?

    But I dont like the idea of copper and aluminum touching in the casting, bathed in salt water.

    I have no help for you friend, but thanks for sharing such an interesting problem.
     
  7. Tharayman
    Joined: Dec 2020
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    Location: North cape

    Tharayman Junior Member

    Removed it because I changed a leaky head gasket. had it sandblasted and painted while I was at it.
    Only fresh water with green antifreeze on the water side. Direct salt water cooling is suicide IMO.
     
  8. Tharayman
    Joined: Dec 2020
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    Location: North cape

    Tharayman Junior Member

    While trying to tackle an internal leak in the manifold, I decided to remove the pipe. Seems like it has broken off from the inlet stud, and has reached all across the manifold. To what use I do not know!
    vOA4oNwgRQKGL48MlNvLLg.jpg
    byC3DQGjT+O1xhBe5LHaBg.jpg
    V0LiONSsQ3GVFqfQEMP1gw.jpg
     
  9. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    I suspect it is there to temper the incoming coolant so that it doesn't thermally shock any of the manifold. But why would you route the coolant supply over towards the outlet like that? Is there a longitudinal baffle that forces the coolant to backflow to the front, cross over, and return to aft to the outlet? And another thing - a cantilevered pipe that long is ridiculous. It has to have had some support, even if it is just pushed through holes in baffle plates. Is there an alternative manifold part with a rear supply and is this how they adapted a front supply?
     
  10. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Both hose connections are at the same end on the manifold. Without that pipe, the water would only circulate at one end and the other would overheat. The pipe's function is to route the water from one end to the other.
     
  11. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    I think you are probably right. I was fooled by one of the photos that just shows a fitting sitting on the backside, but it doesn't go there, it goes where the bolthead is.
     

  12. Tharayman
    Joined: Dec 2020
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    Location: North cape

    Tharayman Junior Member

    The outlet is at the other end, where the exhaust outlet is. So the water will have to move trough all of the manifold even with no pipe.
     
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