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Rust stains leaking around muffler - Man Engines

Discussion in 'Engines' started by CSkipR, Feb 8, 2010.

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  1. CSkipR

    CSkipR Member

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    Recently I noticed rust stains (I think rust) leaking where the exhaust attaches to the fiberglass muffler. Wondering if the clamps loosened up from the cold weather? If so should I just tighten up the clamps. Its on both engine exhausts.
  2. daydreamer4

    daydreamer4 New Member

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    Sounds Like What Is Happening To My 12 Cylinder Mans.the Glass Is Bonded To The Stainless Steel.when It Corodes It Looks Like That.mine Are Being Repaired In Alabama.if You Need Me To Take Them Im Going There Anyway.also Live In Nsb
  3. Capt J

    Capt J Senior Member

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    How often do you hose down/wash your engine room? I usually do that every month or two.....depending on the boats usage. Also the hull air vent screens on the cabo are supposed to be taken out and washed every 100 hours. It most likely is the hose clamps rusting and leaking down. Try tightening them. There shouldn't be anything in your exhaust water to create rust stains on your Cabo. I also spray all brass and metals with a good corrosion guard monthly......like CRC or the one in the metal and bright dark blue can (forgot the name) it's pricier but works well......
  4. CSkipR

    CSkipR Member

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  5. daydreamer4

    daydreamer4 New Member

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    I Live In Between The Two Bridges On House End Of Bouchelle Island.stop By Some Day
  6. CSkipR

    CSkipR Member

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    I haven't washed it down except one time and I shorted out the AC thermostat wire so haven't done it since. Do you spray water over the engine, AC and other equipment? Can you take a hose and spray the hull air vent screens from inside? Have you ever used that saltaway spray on the engine room? Heard of people doing that.
  7. CSkipR

    CSkipR Member

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    What type of boat do you have? Will stop by sometime. Did you know Bob Walker he used to live at the end of the street (forgot name). I'm currently building a house in Vinezia on Via Capri off of the north causeway.
  8. daydreamer4

    daydreamer4 New Member

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    He Used To Be End Of Street,we Live On River Side 2 Houses Down From 67 Hatteras.cant Miss It.the Boat I Mean.38 Ocean And 50 Viking.ocean For Sale!
  9. Capt J

    Capt J Senior Member

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    Lightly rinse the engine, making sure to stay away from air intakes, valve cover breathers, electrical stuff......I sometimes use GUNK on the engines if they're dirty first......stay away from battery charger and exposed electrical stuff......but wash (soapy water) and rinse everything down.......the hull air filters are easy enough to pull out.......you could I suppose rinse them from the inside out......but if you think of all of the air the engines are ingesting and how much salt is in that air it gets on everything.......the water evaporates and the salt stays......mist the a/c's......while you're at it work all of the seacocks........when done (I shopvac the bilges dry) then start the engines and gen and let them run for 30 minutes so the engines burn all of the water off of them and the heat helps the moisture dissappate.......then go in and spray all your un-painted metals and brass with corrossion block.......
  10. Jorge Lang

    Jorge Lang Senior Member

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    I would recommend that you check to see if you have anti-crush sleeves in your fiberglass before you overtighten the clamps. This is a stainless sleeve that fits inside the fiberglass so that it protects it from collapsing. I have seen a number of times that in an effort to stop a leak, clamps are tightened to the point that the now they have a fiberglass issue.
  11. Jorge Lang

    Jorge Lang Senior Member

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    I found this photo showing what might happen if you over tighten a clamp. You can see that the fiberglass has collapsed at the lower clamp. Carl, I hope I have the attchment size correct.

    Attached Files:

  12. Beau

    Beau Senior Member

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    So getting back to the subject of the thread for a momemt, I have 10 cylinder MANs one side showing similar rust. Is Daydreamer's explanation the correct one? Is the rust the result of a stainless steel sleeve at the union?
  13. Jorge Lang

    Jorge Lang Senior Member

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    Can you post a photo for us to see?
  14. Pascal

    Pascal Senior Member

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    there is way too much electrical and electronic stuff on modern engine to hose them down in my opinion, i prefer cleaners or degreaser and rags.

    those trident hose don't always seal well on the fiberglass collectors resulting in small leaks. I use high temp sealant between the hose and glass to improve seal without cranking the clamps to the max.
  15. CSkipR

    CSkipR Member

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    Beau,
    I'm not qualified to answer this since I'm the one who asked the original question. I was not aware of a ss sleeve inside the connection. I did find that my clamps were not very snug so tightened them down slightly.
    Skip
  16. Jorge Lang

    Jorge Lang Senior Member

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    It's not so much the Trident or any other maker of hose. It could be more that the fiberglass is out of round. As far as using a sealant, this reminds me of the old Fram commercial, "you can pay me now, or you can pay me later." Sooner or later, that hose connection is going to need to come out. A sealant will make this job much harder, not to mention the added cost of replacing the hose. I have also seen where clamps are not staggered to make a good seal.
  17. Capt J

    Capt J Senior Member

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    I usually don't have to wash down the newer electronic engines, and do spot clean them a lot. BUT, I have rinsed them down, but only with a light mist, and have bagged the electrical harness connectors if need be. The problem is the salt air is still getting to them. There are some engine foamy degreasers that leave a nice protective residue like Gunk......I've used those and very lightly rinsed and have not had any ill effects on any yachts I've done it on.
  18. CSkipR

    CSkipR Member

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    Exhaust & Muffler picture

    IMG_0633.JPG
    Here is a picture of the starboard side where the exhaust and muffler connect.
  19. Capt J

    Capt J Senior Member

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    Cold weather can causes silicone rubber hoses to contract slightly, and it looks like the hose clamps are loose. You can use a product called WHINK on the rust stains. Just put it on and let it sit 10 minutes, maybe lightly brush it and rinse it off.
  20. Beau

    Beau Senior Member

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    Sorry to be a single issue guy here, but DayDreamer, you seem to be the only one on this thread who has actually looked "inside." Was your rust problem from a stainless steel insert? If so, is this a maintenance item in your opinion. My exhaust hoses have been connected to the mufflers for 12 years - what made you open yours?