06 Chevy Aveo tapping/knocking noise I can't figure out!

[Aveo_Jan]

I have a 2006 Chevy Aveo with a manual transmission and the 1.6l engine. A few weeks ago it started making a tapping/knocking noise that I just cannot figure out. I've uploaded a video of the noise to youtube under the URL https://www.youtube.com/watch?v=N9Rp...ature=youtu.be



I've also uploaded the audio to this post as a zip file. As you can hear the noise is at regular intervals and constant except one out of every 5 to 8 beats is skipped. It does not stop when the clutch is engaged (as if the issue were a cracked flexplate/flywheel). At first I didn't think it sped up when the engine was revved but after listening again it definitely does. First my dad and I assumed it was something with the top end so we took that apart but nothing looked wrong, the torque tensioner was fine, the valves, the head all looked good. We took the head to a local shop as well and they said it was fine too. We ran the car without serpentine belt to see if it was still there and it was. After putting the top end back together we used his stethoscope to listen, the tapping/knocking sounded loudest under the car with the stethoscope on the oil pan. Yesterday we dropped that and thankfully there is no metal shavings in the pan. The connecting rods and weights don't have an excessive amount of play in them. A friend recommended changing the thrust bearings but I listened to the noise a broken thrust bearing would make on youtube and it sounds much too deep to be the same noise my car is making. I may end up having to take it to the dealership to get diagnosed, but before doing that I was hoping someone may have a suggestion for me. Any help at all is appreciated, thanks everyone.

[Mattaveo5]

Check your timing belt. Almost sounds like a piece of belt slapping a cover. Definitely doesn't sound like lifter tap.