siemens freezer?

By inner plastic, I assume that you mean part of the sides top/bottom or door, My 1st question is why is it cracked. If physical damage, Left unattended, over a period of time, moisture will enter the crack, affecting the insulation layer, reducing efficiency, and costing you more money to run. If under warranty, get them out. Other reason for the crack, Again if under warranty get them out. If out of warranty, quick solution, is pipe weld cement, as used by plumbers to join plastic pipe, or hot melt glue gun, cover the crack fully, over lapping the ends. You need to seal the crack, before any more damage is done

SD
August 2011