Hotpoint WD62 washer/dryer very noisy on dry cycle?

My Hotpoint WD62 washer/dryer is making a lot of noise, only on it's drying cycle, best decribed as a constant (extremely noisy) whine. I took the top cover off to identify the cause and it's coming from either the small motor located towards the rear left hand side as viewed from the front, or what looks like an impeller (housed in a plastic case) just behind and driven by the aformentioned motor. Is this a worn bearing or a blade grinding on something?