The invention relates to a fan housing for an air-flow heat exchanger having a fan blower comprising an axial-flow fan and a drive motor, the blower being connected to the fan housing by struts and the struts having a cross-sectional profile with a front edge and a rear edge. On embodiment includes an edge defect detection unit, an optical inspection unit and a processor unit. The intake valve is communicatively coupled with the cylinder head. Within the stack, the first fold configuration is different than the second fold configuration. The elongate hanger resides in a substantially vertical orientation.