Yes your right the raw water gets pumped through the heat exchanger then through hoses to the exhaust manifolds outer cavities then back out to the lake. The anti freeze or coolant side of things stays in the engine block. in the intercooler there's copper pipes that the anti freeze passes through as the lake water passes around in the intercooler. Yes the lake water is always being expelled through the exhaust manifolds. I hope that helps?

​@@marinerepairandinfohow can I do the swap to closed cooling system with my 91 206 cobalt. 5.7 mercruiser