A heating apparatus in an injection molding apparatus comprised of an injection molding machine that injects injection fluid to a heated manifold that distributes the injection fluid to one or downstream nozzles (40, 1020, 1024), the heating apparatus comprising: a heatable sleeve or jacket comprised of a sheet of highly heat conductive metal material, the sheet or jacket having opposing sheet edges, the sheet or jacket being bent or formed into a heating cylinder having a central channel having an interior circumferential wall surface and a selected longitudinal length extending from a downstream end to an upstream end of the heating cylinder, wherein the central channel is formed into a configuration wherein a selected nozzle is received within the central channel and the interior circumferential wall surface of the channel engages an outer circumferential wall surface of the selected nozzle, the sheet has opposing sheet edges (14r, 14l) that are disposed by the bending or forming into a select arrangement or position relative to each other upon reception of the selected nozzle within the central channel, the apparatus includes a stabilization ring or cylinder having a central ring channel having an inner ring circumferential surface, the stabilization ring or cylinder being adapted to receive a selected longitudinal portion of the downstream or distal end of the heating cylinder, characterised in that the stabilization ring or cylinder is adapted to engage or mate the inner ring circumferential surface with an outer surface of the heating cylinder extending along a predetermined length of all or a portion of the selected longitudinal portion of the downstream or distal end of the heating cylinder, the predetermined length of the selected longitudinal portion selected such that the opposing sheet edges (14r, 14l) of the sheet are disconnected over a selected portion (SPL; SPL1; SPL2; SPL3) of the longitudinal length of the heating cylinder. a heatable sleeve or jacket comprised of a sheet of highly heat conductive metal material, the sheet or jacket having opposing sheet edges, the sheet or jacket being bent or formed into a heating cylinder having a central channel having an interior circumferential wall surface and a selected longitudinal length extending from a downstream end to an upstream end of the heating cylinder, wherein the central channel is formed into a configuration wherein a selected nozzle is received within the central channel and the interior circumferential wall surface of the channel engages an outer circumferential wall surface of the selected nozzle, the sheet has opposing sheet edges (14r, 14l) that are disposed by the bending or forming into a select arrangement or position relative to each other upon reception of the selected nozzle within the central channel, the apparatus includes a stabilization ring or cylinder having a central ring channel having an inner ring circumferential surface, the stabilization ring or cylinder being adapted to receive a selected longitudinal portion of the downstream or distal end of the heating cylinder, characterised in that the stabilization ring or cylinder is adapted to engage or mate the inner ring circumferential surface with an outer surface of the heating cylinder extending along a predetermined length of all or a portion of the selected longitudinal portion of the downstream or distal end of the heating cylinder, the predetermined length of the selected longitudinal portion selected such that the opposing sheet edges (14r, 14l) of the sheet are disconnected over a selected portion (SPL; SPL1; SPL2; SPL3) of the longitudinal length of the heating cylinder.