Maybe I got my terms wrong,

but on the belt it winds round about three (I can't quite remember as it's a while since I looked under the bonnet of a Rivage) pulleys, tensioners, big roundy things, call them what you want, but the bottom circular thingy bob was fooked as it's a sealed unit and the oil in the bearings had obviously dried out. Replaced that and the screeching stopped.
Is that a better explanation ?
