E36 328i V-belt tensioner

[LPM320]

Hi Guys

My upper v belt tensioner pulley (The one above and to the left of the alternator) on my 328i e36 has started making a chattering noise, and upon further investigation i found it makes a high tensioned metal to metal friction noise when releasing tension off the pulley. So for saftey sake,i would like to replace it.

Anybody know the procedure, or even a link to a D.I.Y?

Thanks....