An air-cooling method is provided which includes providing a heat exchanger door and a catch bracket. The door is hingedly mounted to the air inlet or outlet side of an electronics rack, and includes: a door frame spanning at least a portion of the air inlet or outlet side of the rack, wherein the frame includes an airflow opening which facilitates airflow through the rack; an air-to-coolant heat exchanger supported by the door frame and disposed so that airflow through the airflow opening passes thereacross; and a door latch mechanism to selectively latch the heat exchanger door to the rack. The catch bracket is attached to the rack and sized to extend from the rack into the heat exchanger door through a catch opening, and the door latch mechanism is configured and mounted within the heat exchanger door to physically engage the catch bracket within the heat exchanger door.