Hey guys
I am from taiwan, My English isn't very good, please don't mind.
My 2014 E400 M276 biturbo with 74000 km. Shell HELIX ULTRA 5W-30 (MB-approval 229.51)
01/25/19 replaced the Both sides chain tensioners and Camshaft adjuster X4


Does this engine noise sounds normal to you? I took the car to the dealer and was told no error code has been generated, They told me not to worry.
There is no excessive metal debris in the oil, no smoke on the exhaust tips, no vibrations, the fuel consumption is consistent with what the manufacturer specified
Anyone with knowledge of the M276 have advice on what the common flaws are with this engine? Is there anyone that has had this problem and found a solution? All answers is appreciated : )

MBUSA released attached bulletins that you may want to discuss with your MB dealer.

Thank you for your reply

My Engine number is 276820 30 041220

I have confirmed with the dealer no emergency recall : )

My 2015 E350 makes that same noise and when I asked the dealer about it I was told it was normal which I don't believe

my previous car was a W211 that once started making this exact noise. My mechanic told me it was the belt tensioner and showed me how it jumped back and forth while the engine was running. However once he started taking it apart, it turned out it was the A/C compressor clutch - it was on the verge of falling off

My 2013 E350 makes the same noise. I took it MB Long Beach and I wasn't satisfied with the explanations I was given, so the service lady assisting me had the shop foreman come out and talk to me. He assured me that by the time my model was released, MB had fixed the belt tensioner issue and the M276 has a high compression ratio and it's literally dieseling. Basically he was telling me it sounds exactly as it should. They waived a few charges without me asking, and obviously left money on the table by standing by their diagnosis, so I can't help but to believe them. Only time will truly tell