I recently purchased a 2009 CRV EX-L AWD with 80,000k (50,000mi) on it. It drives great.

One thing I noticed though: when I first start up the car and it's idling, i can hear a slight whirring sound like a motor running. It goes away when I start driving and isn't really an issue otherwise.

Any ideas on what it could be or any more info I should post?

Thanks!