Start up sounds

[Volvoc30t5]

Good day.
Recently my Volvo has been sounding very strange and loud on start up. It's not that whistling sound, but rather as though things are tapping together, after some time it goes away, but then a loud constant sound still remains.

My mechanic said I need to replace the vbelt, tensioners and gear box mounting. Does this sound right?

Any ideas.

Please help.