1983 300TD Mercedes-Benz question

[dracs]

Hello,

I just got a diesel car. Whenever, I go over uneven surface, I can hear humming noise(like wind chime, christmas bell). It may be present in general but may get drowned in other noise. I have to leave my foot over accelerator and let it glide over uneven surface ho hear. I hear from left side only.

Also, is it normal that the car makes click click noise( balloon against bike tire, paper touching blades of table fan) when accelerating. Mechanic said it is normal because diesel engine are noisy? this is the video below.
Noise while accelerating - YouTube

Friendly folk at another forum suggested exhaust manifold for video above but mechanic confused me.

Any ideas? I have 7 days experience owning any car.

Thanks,