The car has been totally sound up until the 3 year warranty came and went. The car is an 05 model and has done very nearly 50K. It has developed a sound that would suggest the timing belt is slipping. But on closer inspection it seems to be coming from a round "thing" that is located on the left hand side of the engine near the timing belt. This thing just goes backwards and forwards very quickly and squeaks and sounds like a taxi when low revs are put through the engine. Does this problem sound familiar to anyone? All help welcome!