Grand Banks 42 Classic, 1994 mufflers starting to weep a bit, input please

[Taras]

I would run the engines and use a mirror to look all around to determine exactly where the leak is coming from. Could be hose or clamp. If you do need to replace the fiberglass mufflers, don't go with Vetus with the movable elbows. I just purchased those for my boat (because my boat had stainless steel mufflers that were rusted out and leaking). The Vetus mufflers are weak at the elbows while the new exhaust hose is very stiff. The Vetus leaked badly at the movable elbows....its a bad design and too weak for the application. There's a gasket that allows the elbows to twist to fit your application but the gaskets leak. Thankfully, they accepted my return and I went with full, fixed fiberglass mufflers from Vernalift. They are working great and they'll outlast me

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[Irish Rambler]

I'm newer to the forum. I just finished a survey on the boat we hope to buy. One surprise that came up was discovering the fiberglass mufflers are starting to weep a bit. I assume its standard configuration to have two fiberglass mufflers on each side. They are behind cabinetry in aft cabin. Two in series on the port, two in series starboard. The one closest to the engine on the port side is weeping enough to see, feel, and notice residue from dripping on inside of hull. The starboard side is only barely starting, hard to see, no drip residue. The second muffler in series on both sides seem totally fine so far.

This GB has the 3116TA engines, 3300-ish hours. The forward part of the exhaust system was replaced by the current owner when they purchased it and is very nice. I think the hoses that go aft to the mufflers are all original. FWIW, they look to be in great shape.

Replacing these looks like quite a job and probably not one I would want to do, or do alone. Has anyone here been through this with their GB? I would love any advice, experience, thoughts, cost experience, or questions to ask as I navigate addressing this. The surveyor seems to indicate it is something to address during my ownership, but is not urgent. He has lots of GB experience and says its pretty common to see with a boat of this age in salt water of the PNW.

I looked for threads on this before and didn't uncover any that hit what I was looking for. If missed any don't hesitate to tell me.

Thanks in advance!

Get an engineer in to give you an estimate to replace those with new custom made stainless steel insulated mufflers (for noise) and all new hoses, use that as a bargaining chip. Then if you buy you can then do it as your finances permit. I wouldn't touch fibreglass as it will disintegrate over time..
Do it once, do it right !

 

[Taras]

I've had 6 boats with fiberglass mufflers that were up to 30 years old and never had an issue. I'm sure eventually, they will fail but so will Stainless Steel as I just replaced the Stainless Steel mufflers in my current boat. They rusted out and began to weep. Custom Stainless Steel mufflers would be fine but maybe very expensive as compared to off-the-shelf quality fiberglass mufflers. Certainly an option for sure.

 

[kapnd]

In my years of boat repairs, I’ve replaced far more leaking SS mufflers than fiberglass.
Over tightening the clamps and aged hoses are the most common causes of leaks in exhaust systems.
I will use fiberglass tubing over hose wherever it’s practical, as the natural tendency of flexible tubing is to sag between supports, trapping water and hastening the demise of the entire system.

 

[Irish Rambler]

In my years of boat repairs, I’ve replaced far more leaking SS mufflers than fiberglass.
Over tightening the clamps and aged hoses are the most common causes of leaks in exhaust systems.
I will use fiberglass tubing over hose wherever it’s practical, as the natural tendency of flexible tubing is to sag between supports, trapping water and hastening the demise of the entire system.

I'm afraid the person who made the stainless mufflers wasn't properly qualified, they used the wrong grade of stainless and didn't 'pickle' the welds. Done correctly they would last the lifetime of the engine.