[davidmk001]

Originally Posted by RIPws6

UPDATE!...HERE WE GO!......so I had to run a few errands tonight and low & behold, I heard it again! I had 3 GM techs comb my car over front to end today. There is no doubt my AC belt was defective. They showed it to me.
Its frustrating as hell because when I got up this morning to take the car in, I started it and the sound just wasnt there. Thank god I took it in yesterday to let them hear it when it was ticking away.....so I have GM certified witnesses.....it was doing it. They heard it, and we set the appointment for today (friday) to fix it. The belt was in sad shape and they fixed it....they checked the pulley systems, rocker arms....everything. They figured the belt had to be the cause of the tick they heard, and the tick I heard. When i picked the car up today, it was running nice and quiet on the front end.....but a few hours later. I hear the tick again but this time,...it was fading in and out......probably about 35% there.....FML!
The tick seems to be fading.....or on its way out, hopefully so but the belt didnt cure it. I wanted to put that out there for future diagnosis on similar issues.
At this point, Im not sure if I will take it back to the dealer. Its a real hassle to find a ride to work and back....and the way its going now, theres no promise the car will show symptoms while they have it.

I had this exact same tick. Good to hear that they were able to replace some other parts that may needed changing but not good to hear after some back/forth, the root cause on why you went in is still there....

What this is, is a ‘lazy lifter’. GM used some faulty lifters in the 2010 L99's. There is a TSB issued which states that a customer who complains about this noise is to have dealer check, confirm and then repair (or replace the lifters) fully covered under GM warranty. Like I mentioned I took mine in, the tech searched for such a bulletin in their system found it and I left the car there for the night. The next day they called to let me know that they were able to hear it and going to go ahead and replace. I got the car back and tick was gone and 3 weeks later, has yet to come back.

Hope this helps and good luck.