As the cold snap pushes south it occurred to me lots of people in places that never freeze (like me in Tampa Bay Area) are getting some freezing weather. From what I remember from thermodynamics class a couple hundred pounds of cast iron will have some thermal momentum and not freeze super fast but how cold for how long before you need to worry?

2 or more nights in the teens and not comming up above freezing the during the day will usually be bad news.

If the day time temps are above 40 it's nearly impossible for it to get cold enough/long enough over night to do any damage. If the day time temps hover at 32 or less then drop more over night(s) then you'll likely have a problem....
We'll find out how well Virginians winterized come spring. Last year we had a warm winter with only a few days that stayed below 32...this year since Christmas we've only had 3 days that got above 35 and all our nights have been high 20's to mid teens.

HAPPY,put a couple 100 watt bulbs ,one on each side of the oilpan,then close the hatch,the heat from the bulbs will keep it above freezing in the bilge.im just south of chicago,its been zero or below every night for at least a week,man this sucks.

Don't take a chance... invest 100$ in winterizing instead of blowing thousands in engines!

I was once told 24 degrees for 24 hours ???
But never tried it
Thumper

one or two nights dipping down into the 20's isn't going to hurt you assuming it warms back up during the day.

I sleep REALLY well knowing that my blocks are full of anti freeze, but you're in FL. If I were you I would either throw a couple lightbulbs in there, or invest in a heater.

Our rule is under 32* for 24 hours.

However for small cold snaps like your getting just putting a 100 watt lightbulb in the engine compartment for the cold night would be enough to prevent freezing.... providing it is lit...

Yes. Be sure to turn it on. LOL I agree. All you need is a something like this to generate a bit of heat for anyone in FL.

Never assume the obvious!!! My employees had me realize that!