antifreeze out of exhaust

[Westdevil]

i have a 1978 mercruiser 470/170
I'm losing antifreeze when it sits up or when its running through my exhaust system. It's an enclosed water system. What would it be? The heat exchanger, the exhaust manifold or a separation plate or possibly a blown head gasket and what's the best way of checking all of this. I would appreciate the feedback.

 

[Autotech1]

Re: antifreeze out of exhaust

Yeah sounds like heatexchanger to me, if it was a headgasket it would be steam. But im a noob so dont take my word.

 

[Don S]

Re: antifreeze out of exhaust

Sounds like a heat exchanger to me. Remove the heat exchanger.
It has two sides antifreeze and raw water. plug off one of the antifreeze passages and pressurize the other to about 10 psi. Remove the end caps, submerge in water and see if bubbles come out