When i stripped my sunroof motor out it was **** full of rust, totally seized! I stripped it down which is a very simple job, 2 screws i think, then removed copper coil from casing, degreased it then lubricated it with plenty of wd 40 then reassembled. On reassembly I covered the whole casing with black bitumen & refitted to roof! Never had a problem since, that was 3 years ago!!!