Disclosed is a liquid cooling module for computer servers, including: a pump, a fan, a heat exchanger, at least two ventilation grilles, an open central longitudinal space between the pump and the heat exchanger that is arranged to facilitate airflow therein from a grille of one short side wall to a grille of the other short side wall, this airflow being driven by the fan, a portion of secondary hydraulic circuit located in the liquid cooling module, for circulating a fluid coolant, including no bypass that would allow the pump to operate as a closed circuit and likely to clutter this open longitudinal space, a circuit control board positioned in the longitudinal extension of the open central longitudinal space so as to be directly swept by the airflow.