An air cooler assembly includes an air cooler having an air inlet manifold, an air outlet manifold, and a heat exchanger core connected at a first end thereof to the air inlet manifold and at a second end thereof to the air outlet manifold. A water separator includes a chamber having a first end and an opposed second end, an air inlet proximate the first end and connected to the air outlet manifold, and an air outlet proximate the second end. A water outlet is formed in a bottom surface of the chamber, and a channel is positioned beneath the water outlet. A condensate outlet is positioned on a bottom surface of the channel. A helical blade has a first end and a second end, and is positioned within the chamber between the air inlet and the air outlet.