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Man Heat Exchanger

Discussion in 'Engines' started by butch w, Apr 16, 2024.

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  1. butch w

    butch w Member

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    Arnold MD
    Need some advise on the heat exchanger bundle. D2848 LE403
    Both bolts on the back of the heat "x"er are removed and there are not any set screws that are in other exchangers.

    All O rings that are accessible have been removed, I have been using a block of wood and a decent size maw and it will not budge. Is there another connection point somewhere?

    I am worried about breaking something at this point, any suggestions are most welcomed. Thank you.


    heat 2.jpg
    heat 1.jpg heat 3.jpg
  2. Capt Ralph

    Capt Ralph Senior Member

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    You are trying to service your core your self, because??
    Yes, it presses out one way.
    MAN had a HE exchange service just a few years ago. If you were/are having HE issues, I would advise contacting a real MAN service center.
  3. butch w

    butch w Member

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    I am doing the service because it is part of the service required, routine maintenance. I am not having issues with the heat exchanger but they have to be taken apart at service intervals other wise they will stay together and not want to come apart.

    I don't anticipate something being wrong with the core, if there is then the core will go to the proper people who service the cores ( usually the man shops send the cores to bundle/core shops who do that type of soldering/welding on bronze etc)

    On my engines I am due for a heat exchanger service, it is now time according to the last records of it being complete....which is removing the bundle/core inspecting and cleaning. I was just seeing if anyone has had issues with them being stubborn on the way out.
    Fig. 4

    Carefully knock pipe cluster out from the other end, using a block of wood.

    4

    63


    Carefully knock pipe cluster out from the other end with a block of wood.




    Figs. 6 and 7

    Pull out pipe cluster.
    Check pipe cluster and, if necessary, clean it; see
  4. butch w

    butch w Member

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    trying to load pics from the service manual.....having a hard time figuring that out also right now

    Screen Shot 2024-04-16 at 11.30.51 PM.png

    Screen Shot 2024-04-16 at 11.30.15 PM.png
  5. Capt Ralph

    Capt Ralph Senior Member

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    Those two back bolts are usually the big restriction.
    If they are out completely and you insist on DIY, get a bigger hammer or Press It Out.
    Keep in mind, the remaining O rings absorb the blows from a lil hammer.
  6. Capt Ralph

    Capt Ralph Senior Member

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    Scary they would show a photo beating a core out from a HE still on the block. The retaining bolts are still in place.
    Unless, it is re-mounted to offer something solid to beat against,,, after these bolts are removed..

    Big vertical presses pay for them selves quickly on these jobs.
  7. butch w

    butch w Member

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    Exactly, the service manuals for the 2848 series says that only the 10 cylinder plant has the retaining bolts. However an acquaintance of mine
    who is a man tech has said he has seen them in the 8's once in a while and in some 12's

    ( I do have the luxury of contacting him with tech questions, but don't want to wear out my welcome so to say)

    So trying to gather any and all information prior to "another call"

    I wasn't taking a chance, so took entire exchanger off to make sure, plus not enough clearance to try that trick in my er.
  8. Capt Ralph

    Capt Ralph Senior Member

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    It was V8-900s I worked on at first.
    They had retaining bolts.
    Since then and never disappointed, there was always retaining bolts on just the few of later H/Es I worked on.

    Some H/Es would never seal back up and finger pointing would never stop.
    I later had a real MAN rep come up to for these services when required.
    He then sent them to Texas for service replacement.

    Years later, I will tell you now, ,,, Never kick a sleeping dawg,, or a MAN heat exchanger that is not leaking or showing issues.

    This includes crank case vents not showing issues.
    I fear in your zeal to keep maintenance up, your close to inserting issues and extra expenses.
    Please consider ; if it is not broken, don't try to fix it,, #2 rule of working on your own engines.
  9. CaboFly

    CaboFly Member

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    Doing cooling system on my 1100 CR V10’s now as well. I am assisting MAN tech and learning what I can to better understand my engines. My guy said those set screws on back are often overlooked. Mine had them installed and we removed them but the bundles still were a bit of work to slide out. Previous mechanic used a bit of rtv with o rings and that pissed my guy off and he said this is what causes bundles to be difficult to separate. He said corrosion of aluminum can also be a cause of bundles or end caps being difficult to remove . Thankfully mine looked good. Starting to go back together tomorrow after several evenings of cleaning up parts and prep for mechanic to be productive. Ordered O rings from Scott Marine Power which is the achilles heal of system. IMG_1430.jpeg
  10. butch w

    butch w Member

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    CaboFly,
    Thanks for your input, to me it's smart to learn these engines and all associated systems and be able to do as many services as you can on your own. Two reasons....you own your engine room, if or when an issue arrives it is typically not at the dock and you will have enough knowledge to know what's going on and temp fix and get back etc.

    Second is that you are not at the schedule of a tech, you can do the work when needed on your schedule. A true man tech is 100 percent needed for many things, but I feel routine maintenance is something someone who has good mechanical abilities should do themselves if they want. Nothing wrong with hiring a tech at all, and there are plenty of things only an expert should do, I just want to do and know my items.

    Mine has a bunch of rtv sealant as well and I am sure that is holding up the show. I am going to build a press box out of lumber and push it out, the wood block and 5lb hammer whacks made me nervous
  11. CaboFly

    CaboFly Member

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    There are so many tricks of the trade so to speak on these engines the good MAN folks know. I like to be a helper and the cleanup guy for all the important stuff engine related. I source the parts and prep the job. I do oil changes and fuel filters myself as the lead mechanic but I am firmly in the apprentice position beyond that unless it is inside the black box and is Boning related.

    Per a private message request attached is pic of set screws and plugs. IMG_1433.jpeg
  12. butch w

    butch w Member

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    I made a press box with and with wood stops and blocks and a jack for the press it came out, Cabo as you were saying it was a large amount of rtv sealant in there as well.

    The block of wood and hammer blows were being absorbed by the sealant/orings and the entire exchanger not being completely stationary.

    All looks pretty clean. there is a small dent in one of the tubes. No creases and not that bad, what do you all think on this.

    1. Omg boat is going to explode get a brand new one
    2. Does not look bad don't worry
    3. Send to a shop that can braise/weld etc

    bundle.jpg
  13. Capt Ralph

    Capt Ralph Senior Member

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    Even without the extra issue of RTV, pressing the cores out was the safest way to get them out.
    Old factory O rings were tough enough by themselves.

    Get a magnifying glass over that dent. Look for any fine micro cracks.
    Check out the tube ends also for still a tight fit and no odd stains.

    Either somebody was lazy or had a problem requiring a previous service AND using RTV.
    You want to clean and inspect the O ring areas very well.
    Clean up with fine wet/dry if needed but a near polished area.
    We used lots of water based grease when assembling. With the lube, the O rings won't roll or twist.
    mapism likes this.
  14. butch w

    butch w Member

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    Thanks, will get a mag glass on that for sure. I have great success with Alco-Metalube grease in any and all marine applications. The mating surfaces are going to be like brand new when I am done cleaning them.
  15. mapism

    mapism Senior Member

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    Can't improve on what CR already suggested.
    But if I should pick one of these, I'd go for 2.
    Doesn't mean it's not worth checking it as CR explained, mind!
  16. ChiTown

    ChiTown Member

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    When I had mine done the tanks were sent out to be machined to clean up the sealing services. Seems a common issue causing leaks. Demann in Wilmington handle the rebuild.