2008 Tiptronic TT with 62k. Started noise about a month ago. Pronounced when cold for about 1.5 minutes. It's a rattle. Mech thinks it's the timing chain. It stops rattling when warmed, but I've started to hear it in low speeds despite exhaust drone. I've tapped cat, cleaned out pebbles, checked all heat shields. Could it be Cat despite not hearing anything loose? Could it be tranny? Thanks.

YouTube link
https://youtu.be/QsOHsqbk_dw

 

Noise started before the most recent oil change. Car drives fine, pulls hard, no codes.

 

An audio recording would be really helpful. It cold be tensioners taking time to pump up, if it were a loose chain I would expect constant noise.

Have you isolated it to one side of the engine or the other, or is it coming from the center. If center have you made sure the noise isn't on the accessory belt? (You can even pop that off and run for a minute or two to see). If you have a mechanics stethoscope, see if you can localize it.

Ed

 

Mech already listened with stet and thinks it's the timing chain. Sent the link to Sambo and he does not think so. Comes from rear right. I think it resonated to the front of car once when listening. Already removed belt to check tensioners. Wondering if transmission fluid is low and expands once warm, stopping the noise.
Error trying to upload video here. This is the YouTube link.

 

Sounds like a heat shield/thin metal of some sort rattling