Hello All...figured I'd post up here to see if anyone has any thoughts...seems like a few different sets of eyes on this forum than others and lot of helpful posts.

In any case, I was just starting to diagnose a light clattering noise on my RS6 about 6 weeks ago and then had the suction jet pump blow apart....of course that meant an intake pull, but wasn't as hateful of a job as I was expecting from other posts, mainly just time and working carefully. Unfortunately, it didn't give me time to try and figure out the source of my noise before it barely ran due to the vac leak...

A bit more history...I've had the car now for about 5 months, but haven't had that much time to drive it. Several weeks after the purchase, the rollover valve started leaking on the fuel tank, car sat for about 3-4 weeks waiting for Audi to get the kit to do the warranty repair (basically a big blob of epoxy/glue to seal it). After getting the car back, my son (and co-owner) made a few 30-40 mile highway trips to work and back along with some around town driving and then the suction jet pump blew, so it sat again for another 5-6 weeks until we had time to work on that at home.

I first started noticing the clatter after the car sat for the first round with the fuel leak repair. Upon startup, I expected a little lifter noise, which I got and pretty quickly went away after good oil pressure and warm up. When the car is parked and at idle, there is no noise, but when you give it a light rev, say to 2k, when it settles down, there is a definite clatter from about 1500 down to 1000 and gone at idle. Now that I have time to pay more attention to trying to diagnose and having the car drivable again, I took it around the block up to 25 mph or so and noticed that under load from idle and giving it throttle, I'd only hear the noise from 1000 to 1100 rpms and then gone, but not noticeable when decelerating in gear.

While diagnosing the vac leak, we checked the valve timing, and all was good there, so I don't think that it is cam tensioner shoes, although the noise seems to be back on the passenger side rear where the chain is on the head. Other thoughts would be a bad lifter, as that is what it sounded like on my old Yukon (which was notorious for that upon startup for about 15 seconds when cold), or possibly a wastegate flap.

A bit on the car...it has 102k on it, always garage kept...excellent overall shape and was a pleasure to work on with no rust or frozen bolts like my other A6 with 200k that lived in NY State...
Oil change was done by PO about 500 miles ago with Motul oil (unknown weight) and Mann filter. Timing belt done by a pro shop at 98k. Thinking of doing another oil change with BND to start as it can't hurt anything but the wallet.

Here's a quick vid of the car in gear with my foot on the brake which recreates the sound like when driving at low speed like accelerating from a stop or slow coast.

Any thoughts are appreciated, thanks! ~ Eric