hello i hope this is the right place to post.
i bought a 2001 slk 230 64,000 miles, yesterday from some guy and i didnt notice the noise until later.

the noise seems to come from under hood and specifically the engine.
the other noise is a hum that appears to come from the back window or the trunk.

here is the video with audio of what i am talking about.

http://www.youtube.com/watch?v=DVMpSESRDqM

i drove 110 miles to work and i am worried to drive back home and back to work tomorrow where the mechanic is, if you have an insight i would appreciate any advice! it will also be helpful if i knew what i am dealing with before i paid $115 an hour for diagnosis (they said it will be 1.5 hours to diagnose).

thank you in advance!