If a Turbo was going bad it would not take long to fail. Hence, you wouldn't hear the whirring sound. The Turbo is located just in front of the firewall near the middle of the engine and lower, so it's likely it's just the normal turbo noise. However, without you actually making a recording of the sound and posting it here for us to hear, it's a moot point.
Just a couple of questions;
1. Does it make the noise when you're at idle setting still? (If so, open the hood and listen to the sound of the engine at idle or under a above idle load.)
2. Do you hear it and does it increase on acceleration or when you press on the accelerator?
3. Are you utilizing the AC regularly.
4. Are you utilizing the radio on a non-channel, other wise an open air channel without knowing it?
5. Check to see if you are and if you are near a high EMF output tower or cell tower.
6. Check and see if there is anything in or around the electric radiator fan shroud, you'd be surprised what can get in there sometimes.
Reason why I'm asking you these questions are; you really haven't given us a very good description of the location of the noise other than in engine, or provided a very good description. It could be a number of things and not all bad.
It's certainly not a bad turbo by your description so far. When a turbo fails, it does so dramatically and quickly. You'll know it also, it's very distinctive in nature. So if it's been around for awhile, (3 months) it's not a turbo failing, you can be assured. If it's at 90 degrees ambient temp outside or less at start up it might be related to the radiator fan operation. All else fails, take it to the dealer and let them test drive it and they'll be able to diagnosis if their is an actual issue or not.