How does freshwater cooling work?

[surferguy001]

In a freshwater coolant system, how does the water being cycled through the block and manifolds get cooled? is it by raw water being pumped by it or what? Also, how much longer does this prolong the life of an engine as compared to raw water cooled engines only used in the ocean? Just wondering

 

[NHGuy]

Re: How does freshwater cooling work?

Raw water cooling uses the water around the boat through the block, exhaust, and risers to cool things. Closed cooling uses a heat exchanger as a "radiator" and runs coolant through the block but still cycles some outside water through the exhaust. I'm not fully versed on closed cooling, others who know more will come on and give you more details.

 

[stonyloam]

Re: How does freshwater cooling work?

It is a pressurized system that works works exactly like your car, except it has a heat exchanger that is cooled by water (moved by a raw water impeller) rather than a radiator that is cooled by air (moved by a fan). A conventional type water pump on the engine circulates the coolant throughout the engine. In mine (470) the raw water only comes in contact with the exhaust manifolds where it exits (and cools them). The engine is cooled by antifreeze and should essentially be unaffected by the raw water environment, other than surface corrosion.

 

[andyh360360]

Re: How does freshwater cooling work?

i have a 84 bayliner capri with a volvo pent aq 125. i have replaced the housing tower and the cap for the raw water cooling. my problem is that it is still leaking out of that cap. i was thinking of cleaning the manifold but not sure. im not a mechanic and i dont understand why so much pressure is building up under that cap. it is causing my engine to overheat in a matter of minutes on the water. but with the garden hose it does not overheat. can someone help me

 

[Don S]

Re: How does freshwater cooling work?

You really need to start a new thread of your own andyh. and not hijack surferguys thread with your question.

 

[Don S]

Re: How does freshwater cooling work?

In a nut shell, The anti freeze side of the system does the same as your car or truck. The heat exchanger uses water from the lake or ocean, instead of air across a radiator to cool the anti freeze.