Froze coolant system?

Okay, at this point you have a couple of options. What I would do is get something like a turkey baster or similar and remove as much of the "coolant" from the reservoir. Then add mixed coolant and start the engine. Let it run 4-5 minutes and shut it off. Wait ten minutes and start it again for 4-5 minutes. What you want to do is get the engine to gently warm up the rest of the system. You could help this if you put a heater in front of the radiator and maybe drape a tarp over it to hold in the heat. Then keep this process going until the hoses are soft and the coolant flows, at that point, drain the entire cooling system and fill it with a 50-50 mix of Dex-Cool and distilled water. If you are in one of the areas that is getting to the -30 below temperatures, you can bump the mix up to a 60-40 mix. If you are in one of the places that is getting hit with the low temperatures now but normally, don't you still want to drain and fill it because a 50-50 mix cools better than plain water does, and it raises the temperature that it can boil at as well.

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars