View Full Version : closed system?
sturgeon1
02-15-2006, 06:58 AM
Hello, i have a mercruiser 470/170 4 cly inboard that has a closed system with antifreeze in it, my ? is are these systems any good? are they better than a open system?
riverhawk
02-15-2006, 08:27 AM
it sure helps to keep engine block from getting full of rust in salt water and easyer to winterize
Boat Doc'
02-15-2006, 11:57 AM
Closed system is always better than an open system. As previously mentioned corrosion resistance and better running characteristics because it can run warmer. Also gives you a hot water source to run a heater.
sturgeon1
02-15-2006, 12:48 PM
boatdoc im new to this closed system stuff, can you explain to me what you mean by HEATER? what does this heater thing your talking about look like & where would it be located?
Boat Doc'
02-15-2006, 02:02 PM
A closed cooling system normally comes with a hotter than stock thermostat- 170 vs 143 degree. The cooler thermostat prevents salt from crystalizing in the cooling passages. With the engine running warmer you can add a heater which has the anti freeze solution running thru coils with a fan that blows the hot air that is generated wherever you choose to route it. Several manufactures offer them. You can contact our parts dept. for further info.
Petrel
02-15-2006, 02:57 PM
A closed system is what you have in your car, only with a heat exchanger instead of a radiator.
sturgeon1
02-15-2006, 08:27 PM
BOATDOC, i was wondering on this closed system i have, what should be drained for the cold weather? i drained the exhaust elbow on the rear of the manifold & the heat exchanger water side, any others that you know of i should drain? thanks
Raw water pump. I would pull the in and out lines and drain them.
Boat Doc'
02-21-2006, 09:12 AM
Sorry i'm late on this, been out of town, you got it covered. If you have water cooled fuel lines they should be checked to make sure they drain.