[AC/DC]

Im looking at at boat with a closed cooling system. Can anyone give me the pros n cons?

[SLIMETIME]

One very very good thing about those are you can run all year long.I had one down on lake cumberland and it never needed any maint hardly and always ran great.That is one boat I hated to sell.But anyways In my mind being able to use a boat in all-weather is a big plus.And it hardly took any work to winterize it hope this helps a bit

[racecarfan]

Im looking at at boat with a closed cooling system. Can anyone give me the pros n cons?

one pro is if you have to overhaul your engine the block and heads will be rebuildable. Here in virginia with raw (salt) water cooling it eats the cylinder walls away were a closed loop system with antifreeze is just like your automobile. cons maybe an extra hose or 2 to possibly leak. mostly pro i would say

[supercrew]

The engines don't require winterizing and no fresh water intake impellers to replace.

[Big_Z]

Raw is used mostly in Lakes and Closed Ocean or salt water use. If you buy a used closed cooling boat make sure block is in good shape. Its also important to note: Some closed cooling boats are half closed and some are full closed systems. New engines come closed cooling because they are more and more Auto fit as I say. With computers and more sensors they have no choice but to build them with closed cooling. I would not run away from a good closed cooling boat. Make sure all hoses are good,antifreeze looks good and do a test run if you can. Also remember they do need to be winterized. If its less then 50/50 then its mostly water!!! Closed cooling boats also run hot. Normal.

[racecarfan]

The engines don't require winterizing and no fresh water intake impellers to replace.

Am i missing something here? Even closed loop systems need to transfer heat somewhere ie heat exchanger. Does this require an impeller?

[mrchristian]

The engines don't require winterizing and no fresh water intake impellers to replace.

Am i missing something here? Even closed loop systems need to transfer heat somewhere ie heat exchanger. Does this require an impeller?

Yes, closed system engines still bring water into the boat, via a sea water pump, to cool the heat exchanger(radiator). Which would have to be winterized.

This post has been edited by mrchristian: 30 March 2010 - 01:42 PM

[supercrew]

The engines don't require winterizing and no fresh water intake impellers to replace.

Am i missing something here? Even closed loop systems need to transfer heat somewhere ie heat exchanger. Does this require an impeller?

Yes, closed system engines still bring water into the engine, via a sea water pump. Which would have to be winterized.

The closed loop system I saw ran with anti freeze so I guess there are a few different systems out there. Dave just break out da cash.......I'm sure we can get a handle on it

[Capn Ken]

Closed system (I've gopt one), as stated, will run slightly hotter, which also usually means slightly better economy. The big benefit is in Salt Water, for obvious reasons) and in longevity in years (not running hours, which would be similar), due to much less ionternal block corrosion and scale. I would definitely consider it a big plus when buying a boat.

Closed systems require winterizing just like raw water cooled systems. The heat exchangers (there's usually one for the tranny too), pumps, hoses and exhaust manifolds are all raw water cooled and will need antifreeze protection. The Antifreeze in the engine block will need periodic replacement and occassional maintenance, just as in your car or you'll have problems with corrosion.

BTW... most systems will have a sacrificial anode (zinc) somewhere in each heat exchanger that will need looking at once in a while too.

[Powerboat1]

Closed cost more to repair and maintain than open in freshwater. There are more places for leaks, corrosion etc.
They are a must in saltwater.
They are a nice set up in freshwater.

[KMC]

The engines don't require winterizing and no fresh water intake impellers to replace.

Am i missing something here? Even closed loop systems need to transfer heat somewhere ie heat exchanger. Does this require an impeller?

the freshwater intake is not so much to cool the heat exchanger as it is to provide a flow of water for the EXHAUST. There are many boats that use "keel" heat exchangers, which are basically copper water pipes run along the underside of the boat, however most boats you see will have an internal heat exchanger which will require raw water supply.

The Exhaust really needs the flow of raw water to keep the exhaust hoses from burning through.

I would definitely prefer a closed system. As Cap'n Ken says, they do run warmer and that does contribute to better efficiency and longer life of the engine. The reason they run warmer is that they use a different thermostat (usually 160 vs 140 or 145 for raw). This is not bad at all - in fact VERY preferential because it also drives moisture out of teh oil, which is one of the main contaminates. The reason that raw boats use a lower thermostat is that minerals will "lock" onto the internal passages when the water gets higher than 140. With a closed system, you COULD run as high as a car (185-192), but boat engine compartments aren't built for those kind of high temps, especially when you have hundreds of gallons of gas sitting next to the engine.

Yes, more places for leaks and a few more hoses, but those little hurdles can be overcome with a little low-cost maintenance.

You do still need to winterize, but you're only winterizing a much smaller portion (the heat exchanger(s), the raw water pump and the exhaust manifolds and/or risers), which takes MUCH less AF than having to winterize the whole block and cooling passages.

Again, as Cap'n Ken said, you do need to change the antifreeze in the engine just like a car, but it lasts MUCH longer than a car because it runs at lower temps. You should be able to go 5 years easy between changes.