I have a 2001 2.3 zetec Galaxy that has covered 90k miles. When the car is started up after standing over night in damp condition the engine produces a shrill noise. The noise stops after a few minutes driving. I suspect (having searched the forums) that this is the aux belt tensioner. However I am unsure if this requires replacement or whether this can be adjusted. If it does require replacement how much should I expect to pay my local garage.