A header (200) for an agricultural harvester (100) is disclosed. The header (200) comprises a frame (104), a cooler assembly (300) supported by the frame for cooling a hydraulic system of the header, and a hydraulic system (350). The cooler assembly (300) includes an air pre-cleaner (400) for receiving air (304) and outputting a flow of air (306), a rotary fan (500, 700) downstream the air pre-cleaner, and a heat exchanger (302) downstream and in fluid communication with a first air output (506, 706) of the rotary fan (500, 700). The rotary fan (500, 700) includes an air intake (504, 704) in fluid communication with the air pre-cleaner (400) for receiving the flow of air (306), a first air output (506, 706) in fluid communication with the air intake, and a second air output (508, 708) in fluid communication with the air intake and spaced from the first air output. The hydraulic system (350) is downstream the heat exchanger (302) and receives an output flow of air (324) from the cooler assembly (300).
