Sea Flush for engine heat exchanger - does it work

Wojtus

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Aug 2, 2020
7
Beneteau 331 Chicago
Hello fellow boat owners; I have just purchased a 2001 Beneteau 331 with Westerbeke 3 engine, fresh water used only, which is in very good condition, but since the engine is 19 years old and I don't know much about service history I wanted to know if it would be prudent to clean the ENGINE HEAT EXCHANGER. I was watching a commercial for SEA FLUSH and looks enticing. I was wondering if anyone has used that product and what you think, when and how often should I clean the heat exchanger in fresh water environment, and what ways/method have you found this service to be done the best. Thanks.
 
Jan 7, 2011
5,523
Oday 322 East Chicago, IN
Congrats on the new boat. I am south of Chicago in East Chicago, IN.

my O’Day 332 was built in 1988 and has been sailed on the Great Lakes all her life. I do t think we see nearly as much build up as those pumping salt water through their HX. I would be more concerned about impeller vanes or other things getting stuck in the HX than other build Up. You could open up one end cap and see what the tubes look like and make sure there aren’t other things stuck in there that don’t belong there. If you see the tubes are Calcified, you could either try the Sea Flush or take the HX to a radiator shop and have them clean it.

I don’t think Sea Flush would hurt anything, but if the tubes are clean, it won’t do much good.

Greg
 
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jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,034
CAL 35 Cruiser #21 moored EVERETT WA
Welcome @Wojtus to the SBO forum. Congrats on the new to you boat.
It can be tough getting a boat without any reference information.
Heat Exchangers are pretty basic radiators. You can buy all sorts of products to clean a unit, but it can be a lot simpler.
Remove it, open it up and look inside. I bought my boat in 2015. It was running ok. so for 4.5 years I just ran it. I decided it was about time to open it up and change the zinc. Well the zinc was gone. and this is what it looked like.
Photos - 1 of 3.jpeg Photos - 2 of 3.jpeg Photos - 3 of 3.jpeg

Zinc gone. A bit of copper corrosion, and mostly clean inside.

Took it to a Radiator Shop. They cleaned it, rodded the tubes. Removed all debris. Painted it. Installed a new zinc and pressure tested the unit. $65. Back on the boat working like a Heat Exchanger should.

Not a big problem and I now have a date and record of the service.

Good luck.
 
Jun 21, 2004
2,846
Beneteau 343 Slidell, LA
Congratulations on your purchase. I have chartered a 331 many times; great boat! without any service history, would be a good idea to flush the freshwater side of the system and replace the coolant. Check hoses for cracks & abrasion. Also remove the heat exchanger and clean it. I used a wire brush from a gun cleaning kit (22 caliber) to clean the tubes. If they are clogged severely, best to have a radiator shop clean it as JSSailem advised. Will have to obtain new gaskets and o rings to reinstall the exchanger. While you’re going thru the system, check/replace the thermostat, mixing elbow, & replace the raw water pump impeller. Again, enjoy the new boat and welcome to SBO.
 
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