How to winterize closed cooling system engine mercruiser alpha one 4,3 V6

[KellyStone]

Hi I am new to the form and appreciate any help.

From what I have research just wanted to go over the steps that I have and was wondering on how to handle the close cooling system?

I was going to put in fuel stabilizer.
Fog the engine.
Darin the water from the engine block.
Drain and replace the oil.
My question is do I do anything with the clothes cooling system? It has green coolant in it now.
Do I need to drain the coolant and replace with antifreeze?

What I also wanted to know was on the other videos I watched they were flushing the antifreeze through the engine block, and I was wondering if I still need to do this?

Thank you so much for any help.

 

[tpenfield]

Welcome to iBoats . . .

It looks like you have a 'half' closed cooling system, which is engine block only. No reason to drain (or flush) the engine block, since that is/(should be) running coolant (i.e. green antifreeze . . . Ethylene Glycol). You should check the strength of the engine coolant to make sure it is strong enough to avoid freezing in your area.

It looks like the exhaust manifolds are getting raw water. So, you should drain those by removing the lower hose. You will want to drain the 'raw water' side of the heat exchanger as well, and any oil coolers that may be along the intake hose. Make sure you store the boat with the outdrive in the down position.

What is the lowest temperature that you see during winter months?

Post the serial number for your engine, as knowing that helps with responses.

 

[KellyStone]

Thank you so much for your help!
I live in Southern Idaho so it gets to sometimes -5 on a bad winter night. But usually pretty mild

On this…

It looks like the exhaust manifolds are getting raw water. So, you should drain those by removing the lower hose. You will want to drain the 'raw water' side of the heat exchanger as well, and any oil coolers that may be along the intake hose. .

Is there somewhere online where I can find diagram of the engine so I know where the exhaust manifold hoses are located
And when I drain them, do I have to run anti freeze through them?

Thank you again for your time and your wisdom!!!

 

[tpenfield]

If you go to Mercruiserparts.com or Perfprotech.com , you can look up your engine by serial number and there should be some information about parts and water flow diagram

 

[KellyStone]

Thank you!