Antifreeze for winter storage

[Cortes100]

When it comes to our winter hibernation, some use AF and others use good old air. So I know lots of people use this type of fluid when storing their boat for the winter. This particular kind is Merc -50F. I do have a few jugs sitting in the shed and been watching how the cold alters the composition. At -25C it was still pure liquid. Now for the last week it's been a little brisk, touching that -40C range and see the jugs are almost frozen. Not solid but a good thick slush, that barely moves when the jug is laid over. Not sure if it will freeze solid, but I sure wouldn't get a good feeling if I had this in my engine with the boat sitting outside.
I guess the point is, don't put all your faith in these products and assume your engine is safely stored away.

 

[racerone]

If it is slush it will move and not form that ice plug / solid block.----The solid block builds he pressure that makes the block go BOOM.

 

[Scott06]

You’ll see many pictures like this asking the same question, typically the label has freeze temp and burst temp. It can get solid as you are seeing, but will not expand and burst pipes or castings. I think where folks run into trouble is when it gets diluted by not draining the block first.

 

[Scott Danforth]

You’ll see many pictures like this asking the same question, typically the label has freeze temp and burst temp. It can get solid as you are seeing, but will not expand and burst pipes or castings. I think where folks run into trouble is when it gets diluted by not draining the block first.

+1 on this......

Ted did a comparison a few years ago freezing various ratios in his freezer and posting the results.

air still freezes at -471F

 

[QBhoy]

Usually two opinions on this and I suppose entirely up to the owner. Main reason I leave filled with AF is to stop internal corrosion when laid up year after year.
each to their own though...as long as it’s one or the other. Just depends on how you feel about prolonging life and condition at least.

 

[Lou C]

In very cold climates (ie below zero F) I would use -100 (burst temp but its really -50 freeze temp) if you don't feel like mixing anything.....but if you don't mind mixing, a 50/50 batch of Sierra PG brand antifreeze, gives a freeze protection point of -26*F you can of course go higher on the AF %age for lower temp protection. It is actually an engine coolant so its better than the storage antifreezes. I mix up about 5 gallons for my 4.3 and its like a little more than half the price of the -100. But, to each his own.