Hi.

I have 2012 E350 Bluetec model (86xxxmile current)

I feel like my car is very good running

But

I don't know why the high pitch sound every time.


I am sure this is not normal sound than other om642 engine

I am live very small town so... Anyone have idea where is coming from this noise?

Thanks

I noticed the same thing a couple of weeks ago, but haven't noticed it since. I'll be happy to hear others' input.
Thanks for bringing it up.