Hello all. I know I've seen this discussed before but can't really search right now. I replaced the radiator/AST/5 hoses this summer and there hasn't been a coolant leak since.

But now this dilemma! I have freeze protection down to 5 degrees using those cheapo meter things. It hasn't gotten below 20 degrees here in a long time so I thought I was safe. It's going to be 8 degrees this Friday!!! I'm sure those gauges are highly inaccurate. The car is hibernating right now outside (not being driven). How worried should I be?? Is it safe??? Should I take it somewhere to have it flushed and filled with more protection? I really don't need a cracked engine or hose or whatever from expanding coolant/water.

Please advise. Thank you!!!

 

The most vulnerable area will be the radiator - it has the least mass and the greatest exposed surface area.

IMO, while you might be OK (the coolant typically doesn't go from liquid to solid in one fell swoop - it goes mushy in between), if it were my car, I would take some additional precautions in preferred order:
1. add and mix in (run the engine) more AF
2. Place heater(s) (heat lamp, block heater, or other) in the engine compartment and under the radiator (be careful not to overheat, melt, or burn things). Even several regular incandescent lightbulbs will raise the temperature several degrees.
3. Shelter the car (even a car cover or heavy blanket will help) so that it retains heat from when it was warmer and radiated heat from the ground/floor is trapped.

If you can't do #1, I would do a combo of #2 & #3.

 

If you're that worried about it, and there is no way you can drain the radiator and pour in more antifreeze, then I'd run the car at night and run it a little bit in the morning. The underhood area is well insulated as Dave says.

I've also found that a garage is very much better than outdoor storage for temperatures. Even though it's been in the teens here lately the bottles of distilled water in my garage have never iced.

another Dave

 

Thanks Daves! Yeah, I guess I'm being a bit paranoid. I'm pretty sure I'm around 60 AF-coolant/40 water which seems about right. I'll make sure to fire it up to warm it up in the evening and in the morning.

 

60/40 should be good much colder than that.

Dave

 

Chart attached.

Dave