[C320-list] Winterizing the Yanmar 3GM30F

[Doug Treff]

Daryl,

Your concern is unfounded.

The 3GM30F is a closed loop system, meaning the thermostat is on the
"Closed" side of the cooling system that always has a fresh
water/antifreeze mix circulating through it.

The raw water side that you need to winterize flows from the raw water
inlet, through the raw water pump, through the heat exchanger, then out
the exhaust to the muffler and on to the outlet. At no time does sea
water ever enter the engine block or thermostat housing. Therefore, your
winterizing procedure is correct.

Have someone watch the exhaust output on the outside of the boat and
verify that the antifreeze has fully expelled the water that collects in
the exhaust system. A good way to help this procedure is to drain the
standing water from the muffler box BEFORE you winterize, using the
petcock on the side of the muffler. That way there is less standing
water in the system to expell.

--
Doug Treff
doug at treff.us

On Thu, Oct 26, 2017, at 01:17 PM, Daryl Hunt wrote:
> My usual process for winterizing the engine is to run -50F antifreeze 
> through the raw water inlet until it comes out the exhaust.  My concern 
> is that this doesn't give the engine time to warm up enough to open the 
> thermostat, potentially leaving water in the engine block.  I haven't 
> seen any comments or procedures to deal with this so perhaps my concern 
> is unfounded?
> 
> -- 
> Best regards,
> Daryl
> 1999 C320 #660 "Believe"
> 
> Rochester, NY - Lake Ontario
> 
> 
> 
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