Sea water cooling - Fresh water flush - Good/bad Idea?

jonrarit

Active member
Joined
18 Oct 2010
Messages
229
Visit site
I'm toying with the idea of plumbing a fresh water "flush" in to our raw water cooled volvo 2003.

The system would be permanently plumbed in and would be a simple case of closing the sea water seacock & opening a freshwater valve fed from the water tanks instead. With the engine running this would flush out the seawater that normally lies in the engine when not in use.

Once stopped, the engine would then be left with freshwater in the cooling system when not in use which I am hoping would add to the longevity of the engine & reduce the scale build up in the cooling pipes.

I'd appreciate the forum's thoughts on whether this is a good idea or not and whether the freshwater would actually make any difference?

JR
 

RichardS

N/A
Joined
5 Nov 2009
Messages
29,236
Location
Home UK Midlands / Boat Croatia
Visit site
I'm toying with the idea of plumbing a fresh water "flush" in to our raw water cooled volvo 2003.

The system would be permanently plumbed in and would be a simple case of closing the sea water seacock & opening a freshwater valve fed from the water tanks instead. With the engine running this would flush out the seawater that normally lies in the engine when not in use.

Once stopped, the engine would then be left with freshwater in the cooling system when not in use which I am hoping would add to the longevity of the engine & reduce the scale build up in the cooling pipes.

I'd appreciate the forum's thoughts on whether this is a good idea or not and whether the freshwater would actually make any difference?

JR

That sounds like a good idea to me. It what many (most?) of us do with our outboards so it can only help. The only downside might be freezing in winter if you do not drain your system at the moment. Fresh water freezes at a higher temperature than salt water so, depending upon your location, you might need to watch this.

Richard
 

jonrarit

Active member
Joined
18 Oct 2010
Messages
229
Visit site
Freezing wouldn't be an issue as the engine is "flushed" with antifreeze as part of the winter lay up. This idea is only for when she is in the water during the traditional April-October season.
 

vyv_cox

Well-known member
Joined
16 May 2001
Messages
25,574
Location
France, sailing Aegean Sea.
coxeng.co.uk
Certainly can't do very much harm. It will take a surprising amount of water to fully flush it and it must be done hot, otherwise the fresh water will simply go through the bypass. Rather than plumb in to your tank, if you have a Vetus strainer fitted above the waterline you can play a hosepipe into it as the engine is running. I flush my heat exchanger that way after haul out.
 

seaangler23

Member
Joined
4 May 2013
Messages
351
Visit site
I have toyed with it, will certainly do it no harm and it will soften any salt build ups in the water gallery's over time, ours ran a lot cooler after a run through the crinan canal last year. Only thing I'd say is fit some sort of one way valve in case you forget to switch the valve off you wouldn't want the crap in your engine mixing with your fresh water
 
Last edited:
Top