C5 A6 4.2 engine tick (video included)
 

Hello fellow enthusiasts, I've come to the forum seeking your guidance. I recently picked up a second C5 A6 as a side project and would like your opinion as to what may be causing a ticking sound.

The noise seems to be most pronounced at the driver-side exhaust manifold, rear, closest to where it's mounted to the engine. I thought it might be the cam tensioner, so I removed, disassembled, and thoroughly cleaned it so that it moved easily whereas before it was difficult to get it to move in any direction. I also cleaned the oil passages in the tensioner so there were no blockages. This didn't help in the slightest unfortunately.

The noise is present with engine cold and warmed up, and increases with engine speed. The engine runs great otherwise and doesn't misfire. The car has about 125,000 miles on it.

I have a vag-com scanner (Amazon Chinese knock-off, but works fine!) and there aren't any codes related to timing or misfire. Really the only codes are for lambda sensors and evap leak, which I'll be happy to take care of once I fix the bigger issues.

Here's the link to the video:
Looking forward to your thoughts, and happy to try any troubleshooting ideas you may have!

To be honest that is almost exactly how mine sounded (2002). I had the sound from day one (82k) all the way until I sold it @ 144k. From my limited research I was advised it would be the lifters and nothing to worry about as long as the sound does not change. I also read about people replacing the lifters just to get rid of the sound which lasted maybe 50k before they started again.
Good Luck!