Winterizing raw water cooled Yanmar 3GM - SailNet Community
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post #1 of 1 Old 09-21-2012 Thread Starter
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Winterizing raw water cooled Yanmar 3GM

I know this has been done before, but I come up with mixed views so asking for updated view. When winterizing a raw water cooled Yanmar 3GM in particular, is it best to remove the thermostat at some point, since the engine won't come up to full temp (doing this in boatyard). If removing it, should I run the first round of antifreeze in whith the thermostat in place, and then a second round with it removed? That is how i have done it in past, to be sure that antifreeze is pushed through all passages including the ones in use while engine cold. I have seen threads that suggest that thermostat should be left in place, or else all antifreeze flow is diverted from some passages and therefor not fully flushed of water.

When I have removed the thermostat in past, I have left it out until spring so that the system would stay filled with antifreeze. If you replace it after flushing, won't there be air left inside?

With the boat wintering in Maine, I always get a little worried that I am going to mess up the antifreeze one year, so I try to be very careful


Mike sullivan
1985 Marshall 22 catboat
mbsl98 is offline  
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