Sometimes, when I turn my blower on to high, something makes a sound that is sort of like a kazoo. I'm hoping it's not the blower motor, but there are ~250K miles on the car so I imagine it might be ready to go. Nonetheless, it sounds more like it's coming from higher up in the dash, and it might be air passing by something that it shouldn't be passing. This doesn't happen all that often, and is more common on freezing cold days in the dead of winter. Once the car warms up the noise goes away, and I can run the blower on any speed without a problem. Does this sound familiar to anyone? Is that indeed the sign of a failing blower motor?