In the video that you posted it says non-VVT engines. Since my 2009 2.2L is the Ecotec VVT engine is there anything else I should look at and is the procedure the same for changing out all of the timing chain accessories?
I have no problem doing the complete timing chain kit and I see that the Cloyes kit is recommended as being like the OEM. After 51,000 miles if the OEM has failed on my engine I'm wondering if I want to replace it with the same OEM quality parts. Does anyone make a timing chain kit with BETTER then OEM parts for the VVT engine?

I pulled the top off of the engine again and the front guide is fine and there is no slack in the timing chain. Basically it looks like what I would expect on a 51,000 mile engine. As I mentioned, I did change the tensioner yesterday even tho I had the new type in 2009, just to be safe. It did not make any difference to the rattling noise I get at start up. Does anyone else have any suggestions on where to look now. There are no OBDII codes and the engine is running great. My only complaint is the rattling noise at start up.
https://cimg4.ibsrv.net/gimg/www.che...5d3af002c5.jpg

Look at:
flex pipe
air cleaner bracket & rubber isolators
Have somebody else start it while you have the hood open to see if you can narrow down, maybe with a mechanic's stethoscope.
fuse box bracket

Took Air cleaner off and started engine cold, using a stethoscope. The flex pipe is new 3000 miles ago. It is definitely a metallic sound but it is light, not like a rod knock. 2-3 seconds and it is gone and will not show up again until the next cold start. I even tried a new ACDelco oil filter to make sure that it was not draining. Serpentine belt and tensioner look good and I would think that if they were the issue both cold or warm starts would be the same. A cold start seems to be when the engine is cold and it has sat for at least 30 minutes, which is why I changed the oil filter. If the engine is warm from a drive, then it has to wait for the engine to cool down before the noise will come back. Don't know how to check the oil pump. Can an OBDII read the oil pressure?

The oil does drain out of the filter, that's gravity.

Could be the balance shaft /tensioner. There's an inspection cover for the water pump that you can pull to check tension. https://www.yourcobalt.com/forums/ma...tensioner.html

That is interesting and my HHR is in that production range. I have a new Gates serpentine belt that I carry around so maybe I'll just put it on and see how things go. The noise is definitely coming from that end of the engine.