Engine Rattling/Tapping

[MattX2C]

Hi all,

I have done some searches over the internet and forums about this but thought I would make a post about it.

I picked up my ZS180 a week ago and plan to get it serviced pretty some as its due the cambelt change.
Anyway, the first couple of days were fine, but recently I have noticed a tapping/rattling coming from the engine both at idle and in gear.

From what I have read it could be;

Loose manifold heatshield,
Broken Manifold,
Failed VIS,

what is the VIS unit?

Is there anything else it could be? Any DIY things to try to solve it?

Is it just a case of tightening a bolt up, or does the heatshield need to be welded?

Any advice would be great.