Freshwater cooling system

[Jungle]

G'day guys,

Pretty new to boating so would appreciate your help. I'm in NSW Australia.

Looking at an 03 Wakeseter with a 5.7l Indmar 340 horses. It has an enclosed freshwater cooling system as opposed to coolant or raw water (I guess)

Just trying to work out whether it makes any difference - i.e is it better or worse etc? No difference?

Any other tips you guys/gals have got in looking at a 2003 - 2006 Wakeseter be greatly appreciated

Cheers

 

[COOP]

Are you saying it has a closed cooling system, but uses water instead of coolant??

Even closed cooling systems use raw water to cool the coolant.

[csleaver]

Closed cooling systems will usually have a heat exchanger filled with a coolant mixture which is circulated through the engine block, cylinder heads, and sometimes the exhaust manifolds.  The raw water pump on the crankshaft pumps seawater through the heat exchanger and exhaust.  The advantage of a closed cooling system is it reduces the amount of corrosion in the engine cooling system, especially when used in salt or brackish water.

[justgary]

6 hours ago, Jungle said:

G'day guys,

Pretty new to boating so would appreciate your help. I'm in NSW Australia.

Looking at an 03 Wakeseter with a 5.7l Indmar 340 horses. It has an enclosed freshwater cooling system as opposed to coolant or raw water (I guess)

Just trying to work out whether it makes any difference - i.e is it better or worse etc? No difference?

Any other tips you guys/gals have got in looking at a 2003 - 2006 Wakeseter be greatly appreciated

Cheers

 

My understanding is that most of the boating down under is in salt or brackish water.  Closed cooling definitely makes sense in that case.  As the other replies said, the engine will have a coolant mixture in it similar to your car.  The raw water pump will cool that coolant mixture via the heat exchanger, then most likely will dump the raw water out through the exhaust manifolds.  The heat exchanger will look like a ~100mm diameter metal tube with a radiator cap on the top.  Coolant will circulate from the block to the heat exchanger via the thermostat housing and returnto the block via the J-hose into the circulation pump.  The raw water will enter from the raw water pump, pass through the transmission cooler, then to the heat exchanger.  Raw water will exit the heat exchanger and split at a tee to go to each exhaust manifold.

If the exhaust manifolds are cast iron, you might consider swapping them to stainless steel (I can recommend Marine Torq, an Australian product).  If the manifolds are aluminum, you will eventually need to replace them, but not nearly as quickly as iron ones.  Please post photos of the engine and manifolds if you are still considering the boat.

[Jungle]

Thanks fellas - much appreciated.

Hopefully inspect on weekend so will send through some photos

 

Cheers