Blue liquid instead of seawater came out of my cooling system ...

[AlanRothenbush]

One of my fall winterization tasks is to empty the seawater from the Yanmar's heat exchanger. I run a small heater in the boat, but it got really cold around here a few years back and a friend's heat exchanger actually cracked, so better safe than sorry.

The task this year got put off as it's been SO warm. But it's about to get cold .. well below freezing for a week or more day and night .. so today, down to the marina I went.

The procedure is simple; pull the hose off the outlet of the sea water pump, let the cup of salt water in the hose leading to the heat exchanger drain into a bucket (just to be tidy) and then blow into the hose until it seemed clear. Replace hose, done.

Only this year, it wasn't sea water that came out of the hose, it was a DEEP BLUE liquid. It was clear, but deep deep blue.

HUH?

I checked the water in the filter basket on the inlet side of the pump; perfectly normal seawater.

But BLUE .. something .. on the outlet side of the pump.

I checked the engine coolant. Removing the cap, it was the expected orange colour. The coolant overflow tank was half ways between low and full, but that's about the level I always remember it to be.

Now, the engine has not been turned over for 4 months or better, so is it some weird algae? Maybe, but as I always close the seawater seacock when I'm away, the water has been sitting in the filter basket just as long as the blue water on the other side of the pump.

So I'm at a loss. And while not freaked (yet), it's fair to say I'm concerned. I don't like it when unexpected and unexplainable things happen on my boat ...

Any thoughts appreciated.


Alan

 

[Davidasailor26]

Just brainstorming here, but copper ions in water make a blue solution. Heat exchanger tubes are likely copper for their heat conducting ability. What I can’t figure out is how the metallic copper would be converted to ions in solution. Usually that takes something like nitric acid, but it’s been too long since college chemistry for me to remember other possibilities.

 

[TimFromLI]

Not sure what that is but antifreeze is usually sticky and has a sweet smell. Most people I know remove the intake hose put it in a bucket of antifreeze and run the engine until the exhaust water comes out pink. That way there's no water in the raw water pump, plumbing, exchanger and exhaust system.

 

[ToddS]

Not sure what that is but antifreeze is usually sticky and has a sweet smell. Most people I know remove the intake hose put it in a bucket of antifreeze and run the engine until the exhaust water comes out pink. That way there's no water in the raw water pump, plumbing, exchanger and exhaust system.

While I do this... and yes... with the "pink stuff"... there are many different anti-freeze formulas/strengths out there, and they're not all pink... purple is certainly common, I wonder if someone else winterized his engine, and did this with blue antifreeze. When I do it, I disconnect the hose (to put in the bucket of antifreeze) between the strainer and the pump, which would explain why antifreeze was on the engine side of the pump, but not in the strainer... Just thinking out loud... I don't know your hauling/winterizing procedure, so I don't know what the odds are that someone (a boatyard employee, etc) did this on your boat. I'm sure you've since dumped the blue liquid... but the smell test (does it smell sweet?) is a good indicator of antifreeze.

 

[AlanRothenbush]

Thanks to all who replied!

I actually thought for a moment that someone else may well have put some antifreeze in the system for me, until I remembered that I have the only key to the cabin and that there's just no one I know who would do so.

It has also occurred to me I may have done so and do not remember it .. I am an old man .. but while my memory is bad, it's not that bad. Also, I'm sure I would have dumped the antifreeze into the strainer bucket on the inlet side, thereby filling the whole system. But the inlet side has clear seawater, so this doesn't seem likely.

(While I now simply blow the system out, my former procedure was to add antifreeze to the inlet while at idle.)

Also, it does not smell like antifreeze; I was .. surprisingly .. clever enough to keep what drained out. It has no smell at all, and it does not feel like antifreeze. By that I mean, most antifreeze I'm familiar with is slightly thicker than water and a tiny bit "oily". This stuff feels just like water.

Well, I suppose I wait for spring and cross my finders that she starts and runs.

Thanks again.

Alan

 

[DArcy]

I'm just following this thread to see if aliens are involved.

 

[Ron20324]

Are you a "blue water" sailor ? Are any Smurfs missing???

 

[thinwater]

That's pretty close to the color of copper II chloride.

What is the condition of the anode in the HE? If it is good, the blue is possibly algae. If it is gone there is HIGH probability of serious stray current corrosion. I've seen this happen when there was work on the engine and an alternator wire was misplaced or such.

 

[NYSail]

Yanmar's don't have anodes....... Sure does look like the purple anti-freeze I use to winterize engine and buy from WM. Interesting to see whats down line in your exhaust water lift/mixer........

 

[ToddS]

Maybe while underway a squid swam up your exhaust stream, through your heat exchanger, and got crushed by the impeller, releasing its ink as it passed through your pump before getting to the strainer... Did you find any calamari in your exhaust elbow?

 

[walmsleyc]

If you have collected a cup of the stuff (as in your picture), then test it with a antifreeze hydrometer. If it is that deep colour of blue and if it were anti-freeze then it should read as having an observable amount of freeze protection. If it reads near 0C/32F, then it's something else.

You could try a flame test on a small drop of it and see if you get blue/green? This would show you if it contained copper II chloride.

Very strange.

Chris

 

[dLj]

If you have collected a cup of the stuff (as in your picture), then test it with a antifreeze hydrometer. If it is that deep colour of blue and if it were anti-freeze then it should read as having an observable amount of freeze protection. If it reads near 0C/32F, then it's something else.

You could try a flame test on a small drop of it and see if you get blue/green? This would show you if it contained copper II chloride.

Very strange.

Chris

The problem with the hydrometer ue is it is only a density meter, it's useful when you know you have antifreeze. To determine an unknown, you would need a refractometer or other method.

Nice on the flame test - easy to do.

dj