Mercruiser 2.5 or 3.0 winterization

[liusigou]

I saw a video pour anti freezen water into engine through hose and without drain it out. Should I drain it out ?

 

[Scott Danforth]

if you dont drain it out, it will bust.

Winterizing Inboard and I/O

Winterizing your engine and drive. Winterizing your boats engine and drive is a lot of work. Not doing it or doing it improperly WILL be very expensive to fix , and that is also a lot of work. Plan on giving yourself the full day to winterize your boat, and don't wait till the last minute to do...

forums.iboats.com

 

[Candy Gramformongo]

I saw a video pour anti freezen water into engine through hose and without drain it out. Should I drain it out ?

According to manual #2, using antifreeze after draining is optional but "recommended." If you do use it, you leave it in there.

 

[DeepCMark58A]

Properly mixed, spend the $ and use real antifreeze and leave it in for corrosion protection.

 

[Lou C]

West Marine has a good article on how to choose the right antifreeze for winterizing based on the lowest temp anticipated in your climate…I used to use their -100 but now mix my own Sierra PG antifreeze using a refractometer. It’s cheaper & just as good & can actually be used as an engine coolant.

Sites-WestMarine-Site

West Marine

www.westmarine.com

Scroll down to the chart where the different products are rated in FREEZE protection not just burst protection.
I mix the Sierra to be good to -30* F with the refractometer. Way more than my lowest temp and in 20 years of using AF I have NEVER had a problem….