Mainship 400 Yanmar 6LY2AN-STP Heat Exchanger Cleaning

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jefndeb

Guru
Joined
Jun 11, 2018
Messages
618
Location
US
Vessel Name
Indigo Star
Vessel Make
2006 Mainship 400
Hello,

I decided to tackle this endeavor myself when I was quoted close to 3K from the local Yanmar center to clean/service my sea water cooling system.:ermm:

The engine was running fine, no temp issues, but I had no record of the cooling system ever being flushed or cleaned so it was important to me, not being familiar with this engine, to start from scratch and getting a grip on whats going on with all this water tubing. Engine hours 2180.

I paid a Yanmar tech for 2 hours just for him to get down there with me and do an inspection and to tell me what the cooling path was. We opened panels to take a peek at heat exchanger, oil lube cooler, transmission oil cooler and pre charge cooler.

Based on what he saw, he said my system was an 8 1/2 out of 10 condition. 10 being a new engine. So that was good news...anyway there was only about 2 or 3 tubes clogged and a few pieces of zincs laying around.:thumb:

I ordered new heat exchanger and oil lube cooler gaskets, 4 gallons of Yanmar coolant and a new zinc kit..and just for kicks I soaked the exchanger & misc parts in vinegar overnight to remove the any unseen buildup. i also painted the components to fight off the corrosion..

So in the end, I paid for 2 hours of labor that was about $350, $175 for gaskets and coolant. But now I understand the system much better.

Anyway, I just thought to share this effort as to help anyone who might be considering this project.

I plan to re install everything this weekend and do a leak test...:banghead:

Jeff in Savannah
 

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Plus next time it will only cost $175.00 and you probably feel better about knowing more about your engine and your capability to fix it yourself.
 
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