Cold start noise.
I just purchased this 2009 Impala and it makes the strangest high pitched winding noise when you first start the car when cold. Its almost sounds like some kind of little jet engine spinning up and once it warms up a little the thing begins to wind down and stop. It doesn't seem to be affecting the performance but it doesn't sound right to me. Can anyone else tell me if this is normal or something I should be concerned about. Dave