A combine harvester fan housing assembly may include a fan enclosure formed as a single unitary body out of a polymeric material. The fan enclosure may include a spiral duct spiraling about an axis, a first axial inlet opening sized to axially receive a fan therethrough and a second axial inlet opening and a discharge duct extending from the spiral duct. The combine harvester fan housing assembly may further include an inlet ring releasably mounted to the fan enclosure about the first axial opening, the Inlet ring projecting into the first axial opening by an extent so as to extend radially inward of blade ends of the fan.