Quote Originally Posted by old man emu View Post
Could the problem be caused by air coming off the extruder fan? Also, should the air pass over the extruder fan from the front of the printer to the rear, or vice versa?
Yeah, the extruder fan is ONE possibility. No mater from which direction the air comes, you should in any case prevent the print from any cool air. This was the reason I changed my hotend to a different type which needs no fan

Another reason could be, that a fan from the electronics (e.g. RAMPS or PSU) get sidetracked by the printer chassis and hit your print in this area. This was the case in my I3 as well, so I made a special box for my electronics where the fan is blowing in a direction away from the printer.