Coolant Loss Troubleshooting

[Jeffrey Cohen]

Background: Port engine currently has 959 hours on it. Approximately, 173 hour ago @ 780 hrs (1.5 seasons) my port exhaust manifold failed causing an overheat condition. (never got an alarm but the code was there).  The end result was having to have the head milled 17/1000ths (it was during covid and replacements parts were not available) and replacement of the heat exchanger (used part with similar hours…best available at the time). 

Since that time I have been watching the coolant level in the overflow tank  recede to the tune of about 1/2-1  gallon over the 173 hrs. Other than that it runs perfectly and all numbers are as expected (fuel consumption, temp readings etc). 

There is no discernible fluid below the engine or anywhere in the engine compartment. Oil Analysis at the end of 2021 season did show a trace of collant in the oil and potassium in the oil but all numbers came down to normal at the end of last season. 

Trying to diagnose this issue, I just removed the port heat exchanger and pressure tested it…no loss of pressure at all over 3 days with about 20lbs of pressure (overkill i know).

 

Whats my next step? Put it back together and just keep monitoring the situation? or do I dig deeper? If so where? Splashing in about 52 days 🙂

 

TIA for any advice. Jeff      

Topic

[Jeffrey Cohen]

They are QSB 5.9 425HP

Really hard to get a good picture while in the boat but hopefully these get you want you need.

 

 

[Tony Athens]

Missing two things———-

 

Exact engine model and a good picture shown teh entire engine, expecilly the exhaust manifild side

[Author]

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