I have an 08 E350 with the M272 engine. I was changing fluids and noticed a possible tapping sound. Any idea if this sound is normal?

Oil level is and has been fine (although the oil filter housing is leaking), oil changes have been done every 5k miles and have only used Castrol EDGE 0w40 European formula.

There hasn't been any CEL/MIL and no oil pressure issues (as far as the car has shown via codes).

Sounds normal to me - how many miles?

Thanks, hopefully it is. It's clocking at around 96k miles.

you could try using mobil1 0-40w next change and see if it makes any change. Doesn't sound concerning

see how the audio pitch changed as you moved camera? Are you talking about that howling noise? I sorta hear a howl near the intermediate idler pulley..... or maybe the audio quality is misleading....

May be the fuel injectors........normal. A couple years after I bought my car in 2005 I also thought I heard possible problem noise from engine. The MB Dealer and third party MB Repair shop all said "normal" sounds. These engines are a little clanky from injectors etc.

Okay thanks. I just did an oil change this weekend (needed to do one anyway) and it didn't make a difference. I'm starting to lean towards this is normal. I've look at YouTube videos and other owners had posted M272 engines with very obvious knocking.

It's not the howling noise. I do have a belt/pulley kit that I've been meaning to install (includes idler/reflector pulleys, belt tensioner, and belt).

I'm starting to lean towards this is normal. I've look at YouTube videos and other owners had posted M272 engines with very obvious knocking. It's a very subtle taping noise, but I can't seem to locate it.

Are you referring to your E500? Isn't that a different engine (M113)? I'm taking it in to my indie MB shop this Wednesday to have the camshaft position sensors (4x) and magnets (4x) replaced and will ask them about the noise. They were working on this car 1-2 months ago and didn't notice any odd noises (then again, neither did I).