Re: Timing Chain Replacement
I think GM screwed the pooch w/ the oil life monitor on this truck. They specify organic oil and the OLM system trips around 13,000 miles in my experience. This is a ludacris amount of time w/ organic oil, but GM says it's "ok". I find this funny because my Corvette has a great OLM system and it's tuned for the synthetic it comes with from the factory. I typically find my car asking for an oil change anywhere from 6000-8000 miles depending on driving and that's nothing for good syn oil.
In my truck I was going to use the OLM until I found out how erratic it is. To make matters worse you cannot view the oil life remaining on the dash, you can only reset it and wait for it to beep when it's time for an oil change.
So... in my case I run Mobil 1 15,000 mile extended performance with a mobil 1 extended performnace high-capacity filter and change it every 10k per the odometer.
I haven't opened up the I5, but when I opened up my LS6 to put my cam etc. in back in January '07 it looked brand new other than a little cam bearing wear... the heads etc were spotless. Nothing like what I'm seeing in your pics.
So... if I had to venture a guess I'll be this truck has seen normal dino oil changed per the truck's OLM.... time for some sea-foam and swap to a good synthetic.
2004 GMC Canyon - DD/toy hauler
2001 Quicksilver Z06 - NASA TTA racecar
2003 Torch Red/Tan Corvette Convertible