A plastic fuel tank including an upper wall, a lower wall and at least two compartments, such compartments being established by a dividing wall including a part of the tank upper and lower walls, this dividing wall having at least opening enabling free flow of liquids between the at least two compartments and at least opening enabling free flow of vapors between the at least two compartments, such openings occupying less than 80% of the dividing wall, the at least 20% remaining of the dividing wall being constituted by at least one kiss point formed by welding together a multiplicity of contact points of the upper and lower walls.