Rattle noise from engine?

[aescilus]

Hi, I've got a 1.25 mk7 and it's started to make this rattling noise which after looking around in the bay I can only see that it may be a bearing or pulley that's connected to the same belt as the alternator. Would really like your opinions on this as afraid it may snap lol, there is also grease on the bearing that touches the belt

 

Here is a video: https://streamable.com/26avom

 

This is what I think it is: 

 

 

Thanks

Ash

[aescilus]

Anyone?

[Aldridge Andy]

All you could really do if you suspect the auxiliary drive belt tensioner could have the start of bearing failure, is remove the belt and rotate / spin each of the connected components and listen for any noises. If it were me and as auxiliary drive belts aren’t that expensive I’d refit a new belt rather than reuse the existing.