Last trip out we had the temperature alarm sound on the Yanmar. Shut off immediately, checked the fluid level - not too low, but noticed that what started as nice clean looking antifreeze is now frothy brown liquid. Checked the intake filter - not too clogged and water was flowing. We limped back at low revs. Any ideas? I'm thinking it could be a head gasket... but then on gas engines there is usually oil in the water, i.e. white slime. Maybe it just bsiled the rust off the block? I will obviously check the pump impellor and have somebody check it over asap. Just wanted to get some opinions
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J
Joe
My 2 cents
Could it be a leak between the seawater and the antifreeze, possibly in the heat exchange? I don’t think this would give you an over heat situation but it could explain the “brown liquid “. Hope you get to the bottom of this problem. Joe LI, NY
Could it be a leak between the seawater and the antifreeze, possibly in the heat exchange? I don’t think this would give you an over heat situation but it could explain the “brown liquid “. Hope you get to the bottom of this problem. Joe LI, NY
S
Steve O.
J
Jon
Thanks...
I had thought that it could be a leak between the fresh water and salt water exchanger... but it wasn't losing enough fresh water for that. A problem with the 310 is that you can't readily see the discharge from the engine - it is below water. The sea cock was clear and I could see water passing, belt was fine too. I thought it might be a slightly damaged impeller - reducing flow. I was going to the Hunter rendevous at Thetis Island this weekend, so I got somebody to take a look over the engine (I'm no expert past the obvious) - he said it was fine, the impeller was fine, it was pumping water fine, no problem with the head gasket. I guess it sucked up a plastic bag momentarily? I didn''t like the look of that brown froth instead of green antifreeze though... the best guess is that it boiled off rust. Flushed and replaced.
I had thought that it could be a leak between the fresh water and salt water exchanger... but it wasn't losing enough fresh water for that. A problem with the 310 is that you can't readily see the discharge from the engine - it is below water. The sea cock was clear and I could see water passing, belt was fine too. I thought it might be a slightly damaged impeller - reducing flow. I was going to the Hunter rendevous at Thetis Island this weekend, so I got somebody to take a look over the engine (I'm no expert past the obvious) - he said it was fine, the impeller was fine, it was pumping water fine, no problem with the head gasket. I guess it sucked up a plastic bag momentarily? I didn''t like the look of that brown froth instead of green antifreeze though... the best guess is that it boiled off rust. Flushed and replaced.
New antifreeze.
Jon: I believe that Yanmar now recommends that you no longer use the green antifreeze. They now recommend that you use Havoline Extended Life (may be called Long Life). This stuff is pink and is suppose to last for 5 years (thats probably in an automobile). Will probably last forever in a boat.
Jon: I believe that Yanmar now recommends that you no longer use the green antifreeze. They now recommend that you use Havoline Extended Life (may be called Long Life). This stuff is pink and is suppose to last for 5 years (thats probably in an automobile). Will probably last forever in a boat.
J
Jon
Don't go over board.
Jon: This is only an advisory bulletin. I don't think that I would be going over board on this issue. The green stuff has worked for most us for many years and has done quite well. I would only change this out the next time you are servicing the cooling system.
Jon: This is only an advisory bulletin. I don't think that I would be going over board on this issue. The green stuff has worked for most us for many years and has done quite well. I would only change this out the next time you are servicing the cooling system.
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