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Discussion Starter · #1 · (Edited)
Ahoy,
This may be a more broader question than specific to Pacific Seacraft boats, but I want to specifically ask PS owners about their experiences with corrosion damage to the exhaust heat exchanger, exhaust elbow, mixing elbow and other damage done below these components (flywheel housing and oil pan corrosion damage) due to leakage and subsequent corrosion.
During my initial pre purchase inspection of a PS37's Yanmar 4JH2E engine, and later confirmed during a survey, I discovered that severe corrosion had damaged the components noted above due to un-repaired leakage at the exhaust elbow/heat exchanger mating surfaces. The exhaust gas and salt water combination was corrosive enough, over time, to severely corrode the surrounding components and also the flywheel housing and oil pan below. Additionally, the aft, port engine mount is damaged to the point of unserviceability. Many other components in the engine compartment are also severely corroded, no doubt as a result of the destructive atmosphere in there during ongoing engine operation with such a leak.
The heat exchanger appears damaged beyond repair as are all downstream components.
Anyone care to comment?
 

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My 1989 boat has had two leaks in the 5 years I have had it that led to dripping on the engine. One was from the Racor and the other from the raw water vented loop. The first was present when I bought it, and had done significant, but cosmetic damage to the boat. The second I just discovered, but I will replace the hoses before it has a change to do any damage. No obvious signs of problem in the mixing elbow area, but I have not had it apart yet, so no idea what it looks like inside.
 

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Our Caliber has a 1997 4JH2E. When we bought the boat in 2010 it used a little bit of coolant. Previous owner said he spoke to Mac boring who told himthat this was normal. We are talking about a few ounces every time the engine is run. We used the boat like this for a year keeping a close eye on coolant usage. On the way back from our cruise in 2011 it got worse. I tore the engine down and foind that the exchange manifold/exchanger had corroded through. I replaced it with one that Yanmar had obviously over engineered. They claim they were not aware of any issue regardless of the new beefier desin. $1000 later and we have not used more than a couple ounces in the last two seasons. Appr 250 hours.

Here is a photo of the leak. I removed the manifold and pressurized the fresh water side. The coolant was getting blown out through the exhaust.

 

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I have owned my 1987 3gm30f for 14 years. Last year I replaced the exhaust elbow which was severely corroded. I also ran Rydlyme (as outlined by Mainesail) for a long long time through the heat exchanger. All seems well now.

JOhn
PSC 31 #28
 

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After time, wear and deterioration of the wet exhaust system components is to be expected. The typical indicators most owners see as an 'end-of-life' sign for elbows, risers, and heat exchangers is a loss of function and/or leakage. The truth is, time for replacement of these components is far ahead of the external evidence.

The challenge is there's no hard timetable for any one engine. It all depends on frequency of use, operating conditions, water conditions, etc. My parts may last longer than yours, but not as long as they do for the next guy. However, on a well maintained engine in a seawater environment, it seems reasonable at the very least to get 7-10 years service out of most these components; longer if the engine is run in brackish water and even longer in fresh.

IMHO, frequent and routine inspections with corrective action at the first sign of something amiss is the best you can do to stay ahead of the game.
 
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