Steel doors, zero insulation, concrete floors, and kinda drafty too....you know a Southern style garage....we don't "do" cold well in Carolina.

Add that to 5-9 degree above zero temps(global warming my butt!), and "Summer" formula washer fluid rated for 32 degrees, you get split bottles and ruined pumps.

I've learned my lesson, now there's a case of -20 rated AutoZone "Blue Juice" waiting to be used from now on.

 

That's why I am surprised at mine. I park outside, the temp got near 0F, with plain water + a little bit of washer detergent (I got a quart of that mix your own stuff and went summer dilution). I am a lucky boy.

 

With the miles you pile on daily Don, does your HHR ever really cool down?

Of course I keep the bottles topped right up at all times, yours may have frozen up on occasion but it had room to expand.

College was a long time ago, and just what ratios of alcohol and other chemicals needed to lower the freezing point of water to X degrees are something I've long forgotten.