My block is drained, right?

[Chris1956]

I generally use straight antifreeze, on the theory that it is diluted by whatever water is in the block. Of course, straight antifreeze is still plenty cold resistant for our winters in NJ.

 

[nola mike]

Agreed, I would do that just to improve the odds so to speak.
One nice thing about having the Sierra PG stuff and the refractometer, is I can mix up custom batches of AF for just such a situation that are stronger in AF concentration. My usual mix is 50/50 with water and that gives approx -30*F freeze point.

Well... Who knows what the ratio will be at that point, given that I don't know what I'm adding it to. I'd like to know if there's actually a problem. Now I'm curious. I don't think I'll have time tomorrow (rainy today) but I may just refill and redrain the whole system in a couple of weeks. No place to get proper PG antifreeze around here anyway. My whole boat is an experiment. I've spent more time talking about this than it would take me to re winterize it 5x.

 

[nola mike]

I generally use straight antifreeze, on the theory that it is diluted by whatever water is in the block. Of course, straight antifreeze is still plenty cold resistant for our winters in NJ.

Point being there shouldn't be any water in the block, I'd rather know that than gamble on AF getting to where it's needed at the proper ratio

 

[Jmunk]

Well... Who knows what the ratio will be at that point, given that I don't know what I'm adding it to. I'd like to know if there's actually a problem. Now I'm curious. I don't think I'll have time tomorrow (rainy today) but I may just refill and redrain the whole system in a couple of weeks. No place to get proper PG antifreeze around here anyway. My whole boat is an experiment. I've spent more time talking about this than it would take me to re winterize it 5x

I’ve found that O’riellys near me actually stocks the Sierra PG antifreeze. I try to capture what I use each year to use again the next year and test with refractometer. Price isn’t terrible, $29 and it make two gallons.

https://www.oreillyauto.com/detail/c/peak/oil--chemicals---fluids/antifreeze/antifreeze/e59e98316193/peak-1-gallon-green-concentrate-antifreeze-coolant/afz7/sierra