Quote Originally Posted by djmarch View Post
When I tore into this, I was hearing noise coming from under the timing belt cover and knew I better change the belt as I was reaching 52,000 miles on the replacement done at a GM dealership. When I removed the covers, the belt had quite a bit of slack between the cam sprockets. Upon further investigation the tensioner indicator was at pre-install, and the water pump bolts were not tight. The old belt shown cracks between the cogs, so looks like I caught this just in time. I did not replace the water pump at this time, only re-placed the O-ring. I guess I'll pull the water pump again and turn the gear to see if I can see any wobble.
What you just wrote changes everything I had been previously thinking - my mistake in assuming you had replaced all 4 parts. And this new information makes your belt-walking problems very easy to diagnose. Your description of what you found indicates that the previous install was a hack job. With the belt having been running loose as you described, nothing was operating according to design, and the bearings in the WP and the 2 pulleys were likely stressed by the out-of-spec movement. At his point, I urge you to install a new WP, idler, and tensioner pulleys. I believe if you do that, there will be no more belt-walking.