1 GM leaking water

[Dick Kobayashi]

My 1 GM throws off a lot of water when operating. It drips down into e pan below e engine at a rapid rate. Hoses I can see look ok. Where is it likely to be leaking from. Also bilge takes on water - 6 inches every 2 days. I suspect this is from water pressure in the system. I welcome any thoughts on this.

[Sea Hunt Video]

Dick K.:

You may want to check the area around the mixing elbow. There could be a metal fatigue leak in or around that area, especially if mixing elbow has not be replaced in several years.

[Frenchy]

Dick, you'll need your detective hat to trace this down. Possible areas are the raw water pump cover, thermostat cover, the mixing elbow
as Roberto suggested, the wet muffler and of course the hose connections. Maybe the exhaust hose is split somewhere.
On a parallel note, a good suggestion would be to replace the standard Yanmar mixing elbow with a stainless one. These are actually the same price or even cheaper than the factory elbow and last a LOT longer besides easing worries about salt water working up into the exhaust valve. That can happen when the mild steel factory elbow rusts and breaks down internally. The outside will look just fine, of course-
hiding what's going on underneath.
Perhaps the leak in your engine cooling system is syphoning in the bilge water. I would
inspect the water muffler carefully for splits as water might have froze and expanded in there. Good luck in your search - Jean

[John #126]

If water appears to be dripping from the water pump, it could be the seal. There are two ports between the impeller housing and engine where the water can exit. I had to use an inspection mirror to look there.

[BrianW]

Check around the zinc in the heat exchanger. My Beta had a leak this year. I thought the zinc was tight enough when I replaced it. Apparently not. Easiest thing to check 1st.

[John Stone]

Stating the obvious...just in case. Make sure the raw water engine inlet seacock is closed when not looking for the leak.

[Northstar1014]

I assume your exhaust elbow has a hose connected to it to introduce raw water for cooling? If yes, confirm if this has a siphon break and if yes, if it is leaking. Mine has one and leaked at one point.

[RC James]

As you are an old hand on this board, I'm certain that you have considered (since others have not yet suggested) that the leak of 6 inches in 2 days MAY be due to a stuffing box issue.
Perhaps a strong ehgine run in Fwd&Rvs for a few minutes each will help staunch the waterflow that you are experiencing. Let it sit for a day after running in gear and waterflow may slow/stop. The 25D is a bear to adjust, especially as we grow older and less supple. Contaminants and time may slow your leak.
I would think that 6 inches of water in the engine pan when not running (if you have the KingstonValve closed) is excessive and would indicate either a bad stuffing box or a Broken Inlet in the Lower Section of the Water Muffler. (I had a hairline crack years ago and had to make a successful fiberglass repair).
Good luck. I have learned to HATE water in the engine pan and bilge, and still find myself chasing down leaks.
As an aside, I replaced the waterpump after a slow leak, but shutting off the water intake isolated it, and the water muffler was more apparent under engine on time than off.

RC

[Dick Kobayashi]

Problem solved: my mechanic discovered that the petcock that drains the water from the engine was bad and replaced it. Thanks all for the advice here.