308 engine sounds

Friends 308 1.6 hdi How should the engine sound of a 110 vehicle be? Do you have a friend who will enlighten me with a video? There is also an oil leak on the underside of the place marked in the picture. "the picture is an excerpt"

It is not a problem to tighten it, but do not force it so that the upper part of the plastic screw sacks do not deteriorate.

Saolasin my brother