2 issues here, not sure if they are related.....Car is a 2007 LS, auto with 67,000 miles.... First up is the rattle. I started to hear a rattle a couple of weeks ago in the front end. More to the passenger side I believe. Its the loudest while traveling between 35-55mph. Seems to happen most when I accelerate or when the car gains speed. I have put the car in neutral going down a hill and it got louder just from the gain in speed. There is a very very slight vibration to the wheel but I felt that before I started hearing the rattle, its very light, might not be related. Ive also rev'd the engine in neutral while stopped and there is no rattle. Only while in motion.

Second issue is the clunk. This happens when I go over bumps or railroad tracks. Even small bumps I can hear it. Also happens if I apply the breaks and quickly release them while slowing down. Its like a pop and it seems more to the center/drivers side than the rattle noise. Just had the car oiled and inspected like a month ago, this was before the noises. But they didnt mention anything going bad. I also heard the clunk a couple of weeks before the rattle started.

 

I have a clunk as well. I hear mine more if I'm turning at slower speeds.. I have heard my clunk is most likely steering shaft. Your clunk could be Sway bar end links or control arm bushings..

 

For the rattle I'm not real sure but just a guess it could be the wheel bearing possibly. The clunk could be the control arm bushings. They are cheap and wear out pretty easily

 

CobaltLS07,

As always, let me know if you decide to get this checked out with one of our dealerships. I'm available to assist in whatever way I can!

Best,
Sarah
GM Customer Service