cold start noise on 02 3.0i

[JayX5]

Whenever I start my car after it has been ssitting for 2 hours or more, I hear a whirling type noise. I first suspected it dealt with the belts. I took it to my bmw dealer and they let it sit overenight and started it up the following morning but they simply stated that they didn't hear anything different. The sound btw is somewhat like a very light whirling/ squeeling. So has anyone ever had this problem on their 3.0s? Please let me know what the problem is so I can address my bmw dealer about this. I will try to get a sound clip of this if possible.