A hydraulic power unit comprising a rear face and a front face spaced from one another includes an air inlet configured to receive air into the unit, and an air outlet configured to expel the air received into the unit. The hydraulic power unit further includes controls configured to provide a user interface. The controls and the air inlet are located on the front face, and the air outlet is located on the rear face. A coupler for a hydraulic power unit, configured to couple a drive shaft of the unit to a pump shaft of a hydraulic pump, includes a first aperture configured to receive the drive shaft, a second aperture configured to receive the pump shaft, and a hub configured to be received in a fan. The hub is configured to fixedly couple to the fan so that the fan is driven by the drive shaft.