process for manufacturing a plastic fuel tank equipped with a pump , by molding a tubular parison cut into two sheets with the aid of a mould comprising two cavities and a core , said process comprising the following steps : introducing the parison into the mold cavities ; introducing the core inside the parison , said core having first been fitted with a swirl pot comprising a housing for the pump ; closing the mold so that the cavities come into leaktight contact with the core ; pressing the parison against the cavities by blowing through the core and / or applying a vacuum behind the cavities ; fastening the swirl pot to the parison using a device firmly attached to the core ; carrying out the final molding of the parison by blow molding and / or thermoforming ; unmolding the tank , and mounting the pump in the housing of the swirl pot . the mounting of the pump is achieved by way of an intermediate part , the external shape of which is standard and complementary to that of the housing , and the internal shape of which is adapted to the pump .