I bought my Cobalt well over a year ago, when I bought it and I would just start to drive the car I would hear a slight knocking in the back, sounding like it was coming from the rear wheels. It would go away after a mile or 2, and didn't seem to be a issue. Ignorantly I was just excited to have a new car and kind of ignored it. Lately the noise has been getting louder and louder, it lasts longer than a mile, especially in the rain. I'm not really sure where to even start looking for the issue, I have pulled both wheels off just to take a look around and everything seems to be okay..anyone else have this issue and solution? or possible diagnosis?

 

Is it loud enough to take a video?

 

took video with the phone sitting behind the backseats. really start to hear it better later on in the video.

IMG_2954_zps35557309.mp4 Video by jaysonbrown22 | Photobucket

 

De nada?

 

open trunk, remove midget, close trunk.


Well, it doesn't seem to change speed which pretty much removes anything rotational. It's metal on metal, so it should be leaving a wear mark, which by now should be leaving rust streaks. First thing I would do if I were sure it was under the car is jack the car up, get under there, look for something shiny with rust streaks off of it.

 

Did you check to see if it were a hungry trunk monkey

 

Heard if u givem a banana he will grant u three wishes.

 

Purge valve.

Actually listening to video it sounds rotational. No vibrations?

 

Purge valve isn't a bad call. It's an excellent call. I was thinking it wasn't rotational because it didn't seem to slow down or speed up.

 

Its hard to tell just by describtion I say purge valve cause that's what "MY" weird knocking turned out to be be when I first got mine. ........That and he sun roof !!!

After watching the video though it sounded rortaional but honestly I only listend for like 10 seconds.

 

It is rotational, and no vibration

 

I'd say the rear twist beam mounts.

 

This, I'm pretty sure it a trunk monkey. I heard this is pyschocams cobalt and man, it is perplexing. But I believe GM even said it was a trunk monkey