Anti-freeze leaking through raw water intake.

[Jim lanza]

I could use some help on a problem that arose when we hauled Encore out to bottom paint. The hull was fouled, but no sign of blisters thankfully. However, just before we put Encore in the slings, the yardman asked me if I knew that antifreeze was dripping out of the port raw water engine intake. I looked, and sure enough, there was a steady drip, having filled up half of an empty paint can. We put Encore in the water, as we had to get it out of the yard, and I decided that we could motor home on one engine (which we did). Once home, I opened the thru-hull strainer and nice green anti-freeze began to flow out. Interestingly, with Encore in the water, there didn't appear to be any anti-freeze leaking from under the boat. (verified by diving under with a mask). So that's the set up.

Now I need some suggestions. Where besides the heat exchanger could the closed system cooling mix with the raw water? I'm at a loss, and could use some suggestions.
Thanks,
Jim Lanza
Punta Gorda, FL
M/V Encore
Albin 40 Sundeck
M/V Encore

[Norseman]

Busted heat exchanger or oil cooler?
I would not sleep good if my tub was leaking coolant out the raw water intake.

[jleonard]

I'm thinking heat exchanger.
Oil cooler is oil and sea water.
Tranny cooler is tranny fluid and sea water.
Exhaust manifold is antifreeze and sea water, but the sea water is at the wet elbow, so likely won't get back to the intake.
Heat exchanger is antifreeze and sea water, and is mounted high on the engine and pressurized a bit so maybe it's draining back out the intake? (assuming Lehman 120)

I guess that's where I would look first going by what you posted.
If you find that's the source of the leak you know the twin engine drill.....better fix the other side as it's not far behind.

Good luck and let us know what you find.

[Norseman]

. Oil cooler is oil and sea water.

But of course: I should stop doing drugs in the middle of the day, no coolant in the oil cooler..

[srcody617]

Has anybody run this down yet? It sounds interesting.

[rebuckley]

Heat Exchanger is really the only thing that makes sense. On the hard, the intake would be lower than the exchanger, and no outside pressure would allow the coolant to leak out of the boat, until the level got low enough. Once the boat is in the water, outside water pressure would prevent the flow of the antifreeze to the intake and would make it "seem" like it is not leaking - but running the engine should force the antifreeze out through the exhaust at that time. I would pull the heat exchanger, and if the leak is not obvious have it pressure tested - but it sounds like it is busted.