A cover (120) for a diesel particulate filter (106) includes a hollow chamber (128) with an open bottom (140) sized to receive the body of the diesel particulate filter (106), and a plenum (156) attached to the hollow chamber (128) to receive a supply of air, and to distribute that air to an air vent (152) formed in the top surface (150) of the hollow chamber (128) to direct the air across the top surface of the diesel particulate filter (106).