120 Lehman when I start up I get coolant coming out exhaust .. just at startup it’s visible...at rest there is small amount that it’s lost in the expansion tank ... I removed exhaust elbow and I think it’s the gasket .. has anyone had this before ?
Coolant exiting my exhaust
- Thread starter slowjoe
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Lepke
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Coolant is usually at 15 psi or more. Salt water is not really under pressure, but has a high flow rate. When the engine shuts down and coolant no longer circulates, the coolant next to the cylinders gets overheated and causes the pressure to rise at a time where there is zero pressure on the salt water side. So the common source for coolant in the exhaust is a small leak between the coolant and salt water in the heat exchanger. Typically it would be seen at startup.
Simi 60
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First time i roded out our heat exchanger i pinched the oring putting it back together.
Shot a load of bright green coolant out the exhaust on start.
Water for about 1 metre back was fluoro green.
psneeld
Guru
Lehman pressure caps are pretty low, 7psi or so IIRC.
But after sgutdown, the fresh water is still under pressure and the raw water isn't.
But which way would the leak go, I am not sure, or if it ultimately goes to both sides of the exchanger.
I replaced the gasket when I installed a new elbow, but not because of a leak.
But after sgutdown, the fresh water is still under pressure and the raw water isn't.
But which way would the leak go, I am not sure, or if it ultimately goes to both sides of the exchanger.
I replaced the gasket when I installed a new elbow, but not because of a leak.
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Tator
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Where did your leak turn out to be at?
Tator
Tator
I changed the elbow gasket & had my heat changer cleaned and tested ... all installed but waiting to put boat in water .. at least another month yet ... hopefully it should be fine ...can’t really be anything else ... I no head gasket is good .. what else is left ??
what_barnacles
Guru
Possible internal crack in the exhaust manifold from heat and corrosion. Also the gasket between the manifold and the elbow. Some manifolds allow for raw water cooling, and need to be blocked off when using coolant.
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