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Quick winterizing question - Thermostat


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In an effort to sneak out in the cold for a few last sets, I like to drain my engine and then leave the boat in the garage.  Once I am 100% sure the season is over I normally run it up to temp, drain and then run on antifreeze to leave full of antifreeze for storage.  I store in a heated unit.  

My thermostat is easily accessible.  I'd like to avoid running the boat to temp and then re-draining.  The way I understand the thermostat and the housing is that if I removed the thermostat and started the engine cold on just antifreeze that I would fill all portions of the engine without running the boat up to 160.  Do I understand this correctly?  Anything dangerous about this method?  

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8 minutes ago, onwi said:

From the top of my head, the J-hose that I think of connects my impeller housing to the transmission oil cooler.  Am I pulling the wrong J-hose?

That one should be removed too.  The J hose connects the thermostat housing to the engine circulation pump.  It is shaped like a J and if you do not remove it then it stays full of water at the low point, as does the circulating pump

 

indmar_57.jpg

Edited by oldjeep
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So pouring antifreeze into the circulation pump will fill the block?  What happens to the water flow in an engine once the thermostat opens?  What isn't getting water when it is shut and what does get water once it opens?  

Thanks for the info.

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21 hours ago, onwi said:

So pouring antifreeze into the circulation pump will fill the block?  What happens to the water flow in an engine once the thermostat opens?  What isn't getting water when it is shut and what does get water once it opens?  

Thanks for the info.

From what I understand simply draining the block is enough to get the circulation pump to fill the block with anti-freeze fed to it from the raw water intake. You shouldn't need to run the engine up to temp. Just drain, hook up the fake lake, and have it suck up 4-6 gallons of AF. I have seen a bunch of other methods on these forums like sending it through the J hose or removing the Tstat and pouring it in but I can't really say if those methods are any easier or not.

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21 hours ago, onwi said:

So pouring antifreeze into the circulation pump will fill the block?  What happens to the water flow in an engine once the thermostat opens?  What isn't getting water when it is shut and what does get water once it opens?  

Thanks for the info.

Engine manifolds always get fresh water, regardless of engine temp and t-stat state. A closed t-stat prevents water from exiting the block. Circ pump basically pushed against a closed t-stat, until the engine warms up and it opens, then hot water starts to move out, fresh cool water enters in. 

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The only reason I want to fill the engine with anti freeze is to assist in preventing corrosion.  Wouldn't I want that protection in the entire system if I'm going to take the step.

I think this more of a question now of understanding how the engine flow really works.  What I'm reading is that when the thermostat opens, it allows water out of the engine.  Hot water exits the engine and flows up into the bottom of the thermostat housing.  It then flows into the exhaust risers and out the exhaust.  Please let me know if this is incorrect.

What I don't understand is how the system behaves when the thermostat is closed.  Obviously new water is being pulled in so old water must be leaving the system.  How does that happen?  And to bring it all around, what is the actual point of the thermostat?  What is being protected by ensuring the exhaust risers don't receive water cooler than the thermostat dictates?

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48 minutes ago, onwi said:

The only reason I want to fill the engine with anti freeze is to assist in preventing corrosion.  Wouldn't I want that protection in the entire system if I'm going to take the step.

I think this more of a question now of understanding how the engine flow really works.  What I'm reading is that when the thermostat opens, it allows water out of the engine.  Hot water exits the engine and flows up into the bottom of the thermostat housing.  It then flows into the exhaust risers and out the exhaust.  Please let me know if this is incorrect.

What I don't understand is how the system behaves when the thermostat is closed.  Obviously new water is being pulled in so old water must be leaving the system.  How does that happen?  And to bring it all around, what is the actual point of the thermostat?  What is being protected by ensuring the exhaust risers don't receive water cooler than the thermostat dictates?

Exhaust risers receive water at all times regardless of thermostat opening.  Thermostat opening just lets the water from the block dump to the risers rather than looping.

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Thanks for all the information everyone.  Hopefully lasts question - What is the point of running the boat up to operating temperature in a winterization.  If I drain the engine first it really makes zero difference if the thermostat is open or closed when introducing antifreeze.  Is running the temp up only vital if you do not drain prior to introducing antifreeze?

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1 hour ago, onwi said:

What is the point of running the boat up to operating temperature in a winterization. 

Oil change as mentioned above, but it is also a lot easier to remove warm hoses for draining.

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