Did a decent amount of driving yesterday for some appointments, come home finally and start hearing this, still new to the W212 engine and figuring it out but this doesn’t sound normal, let me know if you are familiar with this sound good or bad please.

 

things with these cars is everything is all wrapped up, things work and fail together:
the Tensioners
the VVT gear
the CPS sensor
the camshaft wheel of fortune
HPFP+PCV

Mr Rick just went through RATTLE ALLEY or is trying to get out of it finally. He knows

I can testify the M276/8 are really dependent on better oiling where actual viscosity plays a very large role. This engine is Mr. LEAKY, viscosity is the anti-leak.

Guess why is oil involved in this topic??
- The valve timing system rely on oil pressure to counter ostile forces of Bank1-In camshaft.
- Normal oil pressure prevents HPFP from wasting the VVT lock pin on low pressure --
- Jacked up fuel-pump proportioning valve and injection/spark timings

This engine OIL is well worth attention, true?

 

Definitely, not good. How bad? No idea.

Can you try to isolate the area of the noise? I will focus on a few main areas:
1 - Bottom right --> AC compressor/clutch
2 - Center --> Coolant pump
3 - Top front left/right timing covers --> Chain tensioners + VVT
--> If using a "scope" check front of the timing covers and just a bit behind near the "camshaft sensors at the top" -> tone wheel
4 - Back left --> HPFP/PCV centrifuge
5 - Back right -> Vacuum pump

From the video, it seems up front, but more detailed isolation is required. You can use an automotive stethoscope, or a hose/woodstic-scope to focus on a more precise area. CAREFUL with moving parts though.

NOTE: I did not include the alternator. Your decision.

 

The engine sounds pretty smooth, it does at least 10secs of video.
Is there a way you could pop the engine hood open?

( belt idler wobbling... nearest to alternator )