Hi. I have a 2005 cobalt 2.2 that is having some issues. It starts up and runs normal for 5-10 minutes. Once warm there is a loud chattering noise from the passenger side of the motor at idle. Noise is quieter when revving but once your off the throttle the rpms will drop low and sometimes stall. I have read almost every related thread and I am still stumped. I have replaced the timing chain tensioner and balance shaft chain tensioner and looked at all of the chain guides and they seem fine. Any suggestions would be greatly appreciated. Thanks

 

Here is the sound

 

I've got the same thing going on but I haven't replaced anything yet. My cobalt has 260,00 and I just don't want to give up on it. I bought this car band new in 06' and have taken really good care of it. Replaced the fan, fixed 2 misfires and besides the noise, it runs great. Is it worth replacing the timing chain if that's the problem ??

 

I would think a timing chain noise would be present immediately at startup if that was the issue. Have you popped your valve cover off and taken a look?

 

that sounds like head related issues. have you taken off the valve cover?

 

your guide may be broke. we see a lot of vehicles with that noise and the front guide is broken and the chain in riding on the bolt for the guide. there is a plug on the front cover that takes a allen. pull it and inspect the guide. the plug is right in front of the mount.

 

That's what I was reading that the timing chain related problem would happen at startup. Yeah I took the valve cover and timing cover off

 

You see anything off or broken? If you are this far with the timing cover off you have already completed most the work required to replace it.

 

Hard to tell from the video if the noise is only coming from the cam gear area with the engine covers still in place.