I thought that I would post this as I have just cured a fault that has bugged me for a year. The symptoms were a yelp from the fan belt as the engine was switched off, rough noisey idle the belt flapping at idle along its longest free length and belt squeal at idle when useing the steering. I had changed the tentioner and the belt with no effect. Then I read that the alternater has a clutch in the pulley that can seize. I changed the pully and hay presto all is cured