Started up Monday morning and there was a noise sounding like a bearing rattling or something connected with the drive belts. I'm sure that it started when I turned on the rear demist, and stopped about a minute later and been quiet ever since. I've read things about a clutch on the alternator pulley, any ideas if this is a common thing and if it can easily be checked before it eats itself halfway to work....?? When I get a chance I'll have a closer look at the weekend.. If there is a clutch on the alternator, what is its purpose, can't say as I've come across one before??