I am taking my 06 ss/sc to the dealership on Thursday. It is making this odd rattling noise. It almost sounds like a diesel engine.Not sure if its coupler or timing chain tensioner thing. I bought it from carmax last May. So I plan to take it there since I have their warranty. They usually do pretty well and if I really want a Chevy dealership to service the problem I just pay my $75 deductible. Hopefully we can get to the bottom of this.

BTW: I try to stay away from the Chevy dealership. They keep trying to get me to trade my car in for a ss/tc. Just can not afford it...lol! I'd rather save for a house.

 

I'm having similar issues. Sound seems to be coming from where the timing chain is. Its very hard to hear it unless you really listen for it.

 

Come to the dark side!!!!

 

Might just be the tensioner... but that makes a ticking sound, from what I understand.

 

So I ride out to the dealership. My car acts like an jerk sometimes. Me and the service guy take a ride in the car to see if it will make the noise. Nope...my cobalt decided it was fine. However, it always makes the noise when their service department is closed. Anyhow, I showed then a video of what it sounds like from another cobalt on youtube. They agreed with me and said it was most likely the timing chain or timing chain tensioner. But without it acting out right then there was nothing they could do..plus they did not want to charge me for nothing. In the end they said just bring it buy if it ever does it while I am near the dealership and they would jump on it right then and there. Moral of the story...Cobalts are possessed.

 

mine did the same exact thing! took it to the dealership and it would never come on. so i decided to change mine myself. pretty easy to do. here my how-to good luck!
https://www.cobaltss.net/forums/how-guide-43/how-timing-chain-tensioner-203071/