2010 Cobalt LNF - Ever since I can remember there has been a noise that comes from the last half of the vehicle. It starts as you start moving and I would call it a "drone" that sounds "hollow". Almost like metal is contacting metal and transferring road noise from the tires. I have replaced both rear wheel bearings-both shocks-both springs with isolators-complete brakes with rotors-calipers-pads....and tires of course. I was wondering if anyone has ever had this one before...it seriously has me baffled...it's almost like I need to attach a damper on the stock rear sway bar....the way it sounds is like the springs are sitting on metal...but they are not...the rear axle beam bushings are ok...a little cracked...but decent....I have tried a few times relaxing the suspension by backing off bolts and re-setting them....exhaust hangers were replaced...vehicle makes the noise mostly straight...going side to side diminishes the noise somewhat...the smoother the road the less the noise..tires are new and this did this with the old tires ...tires are Pilot Sports....rims are not bent..and are balanced..wheel alignment is good...any ideas?

 

Maybe it's dead coils on the springs smacking around well of course if you have lowering springs

 

are those cork silencer pad things still above and below ur springs? they rip off easily causing noises

 

Stock springs replaced them with another set of stock springs...new isolators on top and on bottom....pulled out subwoofer today no difference...going after the eval canister next.

 

during cruising, or just accelerating?

edit: sounds more like all the time. I currently have a hollow droning noise and did previously while accelerating. turned out to be a bad resonator with my corsa exhaust. now its a bad resonator on my stock exhaust.

 

Conductive Road Noise...appears after about 10-15 mph..all the way up to highway speeds...not as bad at high speeds but feel the other noises over come the initial noise. Sometimes gets a little quieter up a steep hill...and a little louder when breaking. I pulled down the rear seats and it got a little less...put them up a little louder...this "hollow drone" is definitely conductive..

 

wheel bearings or trist beam bushings

 

If it's louder with rear seats up, then it could be a front wheel bearing. My civic has a bad front wheel bearing, but the noise surrounds the whole car and you would swear it's coming from the rear

 

hmm...front wheel bearing....I'm not going to say no...but anything is possible I guess....I'll throw it on the hoist and see if I can duplicate in the next few days....

I was going over the bridge the other day and the steel they use to connect the concrete together made the noise amplify like crazy...

If it is a bearing in the front...it's weird that it does not change pitch swaying the vehicle back and fourth ..and of course there is no play axial....but I won't rule it out...thank you for your input....

I'll drop the rear beam...pull the bolts out...clean them and never seize them and reinstall it to see if it changes pitch...the mounts have been loosened and re-installed ....the bolts have been loosened and reinstalled....

I'm going to pop the trunk also and drive a block just to rule that out as well...