It sounds like a creaking bed and really hard to explain. I've done a search but they don't quite match up with the symptoms my car is showing. This noise comes after the car has warmed up, upon initial start you do not hear this sound. When the car is in park, it seems random in a sense. But when it is engaged into Drive, it becomes a constant. I'm putting this out there as maybe one of you have experienced this sound before and know what it is. I can't exactly pinpoint where it's coming from but it seems as though it's a little more pronounced at tensioners. It doesn't matter whether or not the A/C is on or off, it's still there. I recently got this car this year so I'm really finicky about any abnormal noise I hear, and this definitely fits the bill. Any help is greatly appreciated. I've included a Youtube video below which I took, very short, but you can definitely notice the sound over normal engine operation. (ignore dirty engine )

 

That sounds like a bearing in a pulley going bad....take your serpentine belt off and start the car and see if it's still there...if not then it's accessory drive related. Re install the belt ,bust out a long screw driver, start the car and start listening to the pulleys as they turn but be careful because noises do travel and it could fool u. Last thing u want to do is u end up replacing the wrong part

 

Just as an update, so I don't leave this thread open ended, it ended up being a bad pulley. I bit the bullet, swapped out both pullies, and now the sound is completely gone. Not sure which one it was to be honest, I got them for $120 from the dealer which I felt was a good deal. Thanks for pointing me in the right direction 3RDGENTL757.

 

I have to replace my Belt Tensioner assembly and serpentine belt since its way past the optimal performance range marker. I'm at 159k miles and my mechanic told me that you could try to replace the pulleys but the tensioner is done and the sound will continue.

I have the exact sound, but the whole assembly needs to be replaced since my belt tensioner is done, so it stretched my serpentine belt(accessory belt) so I will need a new one.

Thanks for the post, I even recorded a short video on the sound. So it's the belt tensioner assembly or pulleys.