i have two cold related things. probably(?) not related but posting them together:

NOISE:its just now gotten below freezing at night here, and the last two mornings my car has made this sound coming from the vicinty of the windshield wipers (honestly can't tell if its from inside or outside the car) and its like wind is whipping through a small crack. gets really wining and high pitched. when i slow down (below 10mph?) it stops, but i can be at a higher speed and put it in neutral and the sound continues until i've dropped to a crawling speed. its happened two days now (the first two consecutive days that my car has been able to start!). both days i've turned around and brought the car back home. later in the day when i start up it doesn't happen (which makes me think its cold related). i have been warming the car up for 10-15 minutes before driving in the morning. the sound makes me nervous like something is about to blow or snap or some witch is going to smash through the hood. any thoughts?

COOLANT LEAK: I also have a coolant leak. When I look down at the radiator I can see coolant gathering on the lip below the upper hose, and falling to the ground from there. On the opposite side of the radiator is almost looks like the radiator is sweating or weeping (which I assume is coolant). Does this mean I have to replace the radiator? As long as I check levels regularly (I drive an hour to work) can I put off the radiator l swap till this weekend you think?

Thanks for your awesome advice as usual! I swear one day my car will stop breaking and I'll just answer other peoples questions!