Winterizing anti freeze

[Bad Habit]

 Wondering what to use for anti-freeze to winterize my 4.3 Mercruiser. I noticed the Prestone pink waterline anti-freeze says:

• Not to be used in gas or diesel engines as winterizing fluid or antifreeze+coolant  

[AnglingAddict]

Probably because it is alcohol based which is flammable.  Use a Propylene Glycol based antifreeze for winterization.  I've always used the Starbrite Propylene Glycol stuff and been happy.  They also make an alcohol based antifreeze for water systems only and the packaging looks the same so just be aware.

 

https://defender.com/en_us/star-brite-non-toxic-antifreeze?srsltid=AfmBOoow1kqDlsrmf7_cksGv_ZYYUXbpTtEMa4tl81owjU9fV5dpZZabj3I#615=30924

 

Just looked up the safety data sheet for the prestone RV antifreeze - indeed it is ethanol based.  

 

https://prestone.com/wp-content/uploads/2020/11/SDS834-1.pdf

Edited September 5 by AnglingAddict
added data sheet link

[Papp]

I use the west marine the green colored stuff, it’s over kill but I figured if all the water isn’t out at -120 even the diluted stuff is still strong enough?? I ordered it from Amazon right to the door. I winterize using a bilge pump off the ears an out of a 5 gallon bucket, fire her up let it run till solid color comes out the exhaust, shut her down done!!! Works for for the last 30 years✌️✌️

[Bozeman Bob]

People have put the pink stuff in there freezers and it does freeze . Some mfgs ,if you read the small print , state the freezing point on there product . I would buy regular green anti- freeze and sleep well at night .

[AnglingAddict]

15 hours ago, Papp said:

I use the west marine the green colored stuff, it’s over kill but I figured if all the water isn’t out at -120 even the diluted stuff is still strong enough?? I ordered it from Amazon right to the door. I winterize using a bilge pump off the ears an out of a 5 gallon bucket, fire her up let it run till solid color comes out the exhaust, shut her down done!!! Works for for the last 30 years✌️✌️

I do the same / I use the starbrite -100 stuff and assume that if it dilutes a little I’m still fine.  No issues.  I do use the pink -50 stuff in my water lines, head, A/C unit, washdown  and sink drains.  If something goes wrong there it’s probably only a sift hose and not the fresh water cooling system on my motors….