[worthirt]

Check the individual pulleys, bet there is a bearing starting to go on one of them. Most likely is the tensioner pulley or the idler pulley. My guess it that the cold is the "trigger" for it. Check all the others while you are at it. Belts usually make a "squealing" noise as they become loose, so I'm leaning away from the belt. Check it too though.

 

[worthirt]

Most of your big box stores (Autozone and the like) will have that stuff in stock. As to how long, I couldn't really say. Before you throw any money at it, check to see what the problem is. If there wasn't an issue until it got really cold, you most likely have a little bit.

 

[worthirt]

what kind of coolant did you put in? I know you said 50/50, but there are different kinds and most of them don't mix well. Your car came stock with Dexcool (orange in color), if you put the "green" stuff into it, your coolant will turn into a sludge and the only way to get it out is flush it all.

 

[worthirt]

It would thaw when the car warmed up actually, as coolant usually gets to 190+ degrees. If the water pump fins were damaged as James pointed out, If the coolant was to thaw now, it doesn't matter as the damage has been done.

 

[worthirt]

If the alternator could be the culprit as James has mentioned, You could always take the alternator off and bring it to autozone or something like that to have it tested. The machine they used to test mine had a small belt and put tension on the alternator, granted, if the noise is found, they will try to sell you a new one. But the good thing is that you know what the issue is and can make the decision upon where to get a new one.

Rob