[Ultracrazy]

It only buzz/rattles at low speeds. It doesn't sound like other rattles discussed here. Brand new 2011 Equinox LT with 4 banger.

 

[2010Nox]

It only buzz/rattles at low speeds. It doesn't sound like other rattles discussed here. Brand new 2011 Equinox LT with 4 banger.

Maybe there's a bee with a rattle living in there!

Seriously, what you describe sounds like a vibration of a loose item at a resonant frequency. I find the 2.4L has a distinct low frequency sound when idling and at low speeds. It's so distinct that I can tell from inside my shop which is 70 feet away, that my wife is leaving with it rather than the Malibu or Sierra.

I would first take it to the dealership and reproduce it for them and let them determine what it is and what will be done.

 

[Doogr]

I have a similar noise (buzz) but I found it's coming from a blown right door speaker.
I found it is also temperature sensitive. Worse when just above freezing. I found it's related to low frequencys ie. bass. But the buzz is there with the stereo turned off. So I figure it's caused by the noise reduction sys. and the blown speaker. My nox is just over a year old now so I don't know if any warranty on that part. ( bought all extended) so will find out if covered.If not then I'll look into after-market upgraded speakers.

 

[RIT333]

My nox is just over a year old now so I don't know if any warranty on that part. ( bought all extended) so will find out if covered.If not then I'll look into after-market upgraded speakers.

You should have 3 yr/36,000 mile bumper to bumper coverage automatically.