Blue, did you change the belt tensioner at the same time, or just the belt? I think the TSB says to change the tensioner, too.

 

Ive had this problem on both of my HHR SS. First was the 09 auto and now the 2010 manual. And both under 10,000 miles. Only does it on cold start sometimes, so I chalked it up to being normal. But if there really is an issue then that would be because of the way it was built, not worn parts.
I also changed to a gatorback belt on Thursday so it wouldnt slip when I NLS. Not sure if the noise is still present but I'm sure it is, as it sounds as if it's coming from valve train or the timing related parts.

 

I did the Belt only, tensioner was fine. So far I have had 0 rattle with almost 10K on new belt.

 

So, after having a headache for six months, turns out I was all carbed up. In the winter I drive defensively and never step on it. Since the dry roads have been around, my SS hasn't done it. I'm so glad to have this finally resolved. Thanks everyone for all your help. Mike wherever you are?

Once it's paid off, no more winter driving.

 

Carbon?

 

Ya, Carbon.

 

What was the repair procedure?

 

There really was no repair done. I had the fuel pump replaced four or five months ago, yet it was still rattling in the morning after the work got done.