Heavy white deposites in raw water side of heat exchanger

marksman · Newbie

Heavy white deposites in raw water side of heat exchanger

Farron · Senior Member

Hello Fred,

It sounds like you have a heavy mineral buildup on your heat exchanger core. I suggest removing the heat exchanger core and soaking it in vinegar overnight to remove the build up.

The core should be re-fit with new o-rings. Be sure to clean the sealing surfaces and use grease on the o-rings when you replace the core. Consult the owners manual for instructions on removal and refit of the heat exchanger core.

Zincs should be replaced every year or as required.

I would suggest that you check the condition of the raw water impeller and also inspect the water supply to the engine for any restrictions.

marksman · Newbie

Hello Farron,

I cleaned the core and checked the pump impeller, which still looks new, but I can't say I have ever experienced this kind of deposites before. The engine I replaced with the Beta also had fresh water cooling, but no zink and never collected this kind of build up in the three years I used it. Can this have anything to do with the zink?

Farron · Senior Member

Hello Fred,

We do not know much about your particular application. Are you in salty, brackish or fresh water? How often do you run the engine? Has the heat exchanger been checked or cleaned previously?

While heavy build up on the heat exchanger core is not a common occurrence, it can and does occur.

The attached photos show a very heavy build up that almost completely blocks the core and partially blocks the input fitting.

We can only surmise that this was due to some sort of heavy mineral content in the local waters.

There is a possibility that stray currents could be causing the buildup. That would need to be checked by a competent marine electrician.

marksman · Newbie

Hi Farron,

Your picture looks very similar to my components. I am in Salt, Puget Sound. My engine doesn't get used very often as we sail most of the time. Less than 50 hours in two years. Because of the low hours, I haven't had the core out before this, live and learn. My coolant zinks go away in about 6 months, but my shaft zink lasts around 14 months, not that they should be compared. AC and DC grounds are not combined. Since the build up is mostly in the inlet/outlet end I suspect the byproducts of the zink deterioration are what is collecting since the unit doesn't get flushed very often, particularly in the winter months. Freezing is not a problem but looks like I should drain the raw water side anyway for winter months.

Thank you for your insight,

Fred