Hello all I do hope someone can help. I am trying to find the fault with my neighbours DC14. It is making a high pitched roar when on but there is no loss of suction. The filters seem fine and the regular trap points are clear. As I use a DC07 I have little knowledge about the 14. I have unclippped a housing on the lower left side which is hollow and circular but with an entrance exit hole. Should there be a filter in here? Am at a loss.