Plastic fuel tank with improved creep resistance and method for the manufacture thereof

Plastic fuel tank having a lower wall, an upper wall and at least one reinforcing element (3) connecting these two walls, this reinforcing element (3) comprising a hollow plastic pillar (3) having an opening in its lower part (1) and an opening in its upper part (2), these openings (1,2) being situated at locations such that they allow, respectively, the filling of the pillar (3) and the degassing thereof.