The invention relates to an oil sump (1) comprising a lower shell (2) intended for containing lubricating oil of an engine, in which a flow of oil, referred to as suction oil flow (I), is sucked up via a suction tube (44) to supply a lubricating circuit, and an oil flow, referred to as returning oil flow (II), falls into the oil sump (1). The oil sump (1) comprises an anti-emulsion plate (8) arranged located at the mouth of the suction tube (44) during a transitional period in which the temperature of the oil is lower than an optimal operating temperature.