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coolant loss

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westirmax

Contributing Member
Sirs:

Strange thing on the spring commissioning. dumped her in and started her up, no issues. Forgot to check the coolant level and she was low, very low. added what I had on hand and she was still low. topped up with water. shes currently still full after running it a bit. No apparent coolant in the bilge. Thinking possible leak in the heat exchanger and its going out through the exhaust ( raw water side). What other possible places? In the oil pan( I should have water in the oil.) only two places nearly a gallon of coolant could go? or in the bilge but its just not there.

if its leaking into the combustion chamber i should have smoke or smell or something?

greg-
 
Crankcase breach will show on the dip stick.
Maybe you could pressurize it to 16-18 psi and listen for the leak with plugs out for head gasket?
 
confirmed oil is clean and full, not foamy ,milky. coolant level is now remaining constant. boat was laid up for 4 months this winter, so i guess a very slow drip might evaporate before detection?
 
Obviously not getting into the crankcase. Expansion plug leaks generally will leave a tell tale trail. Coolant level steady after operation and no significant closed system pressure increase can almost rule out intake or head gasket. What's left?
 
A pin hole in the heat exchanger that allows passage under pressure to the open circuit( raw water side) but I assume it would need pressure to squeeze it out, no such pressure during the lay up. I will be pressure testing the closed side in a day or two. My mechanic said pull the side caps on the exchanger and look/listen for the blowout, I assume this is after we confirm a pressure drop. No pressure drop no leak on the closed side. ( coolant side). Next plan is to mop out the bilge and put some new engine diapers down and see if there is any dripping/spraying or otherwise indications of an external leak.
 
Re: coolant loss-SOLVED i think

UPDATE:

found leak. was the hoses as they mount to the exchanger. both in and out. Used a pressure tester to bring the system up to 15 psi. Immediately found one hose hissing air. tightened it up thought is was done. 10 minutes later pressure was almost 0. pumped up again and found fluid leaking from the other hose, it was actually running down the hose toward the front of the engine making it look like the issue was in the front of the engine. tightened the clamp and though i was done. pressurized again to find the return from the manifold fitting leaking, I did not get time to repair that leak but its next...Good points its not the exchanger, its not the head gasket and its not the circulating pump...the cap says 7psi so it should be good once i hit the final fitting.
 
Thanks Jeff- the tool was the key! The final hose end was cut back and reattached. Now holds 15psi all night long so 7 psi should be fine.
 
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