I have a 2004 Impala base model with just over 75k. Just last week whenver I turn the car when it is cold I can hear a slight whining noise when turning at very low speeds and whenver I park.I thought it might be low power steering fluid, but I checked it and it was full. My power steering fluid was changed out in the spring of 2009. When the car is on the road and I turn I can't hear the whining noise. I can only hear the whning noise with the radio very low or off. Other than that, currently the car runs and drives fine. What could this possibly be? Is this anything to worry about or is it just an annoying noise? Could it be a faulty power steering pump (that is what my friend thinks)? Any suggestions on this is appreciated. Thank You.