Odd sound, need help

My car has started making an odd sound. The only way to describe it is it sounds like someone blowing across the top of a drink bottle. It doesn't do it all the time and when it does, it is constant. It doesn't change any with throttle response. It also sounds like the fan motor is making a loud winding down sound when shutting off the car. Could the fan motor be going bad and making both of these sounds?

If I get the chance, I'll try to make a little video of it.