I have had problems with PLA sticking in my Printrbot 1302 extruder due to heat issues. This is a common problem and there are lots of fan mounts available. All of these mount the fan at an angle or use 25 or 40 mm miniature fans. I wanted a more optimal solution so I made a fan mount that replaces the original wooden side parts of the extruder assembly. The new parts make it possible to mount a 50 mm fan right in front of the extruder for maximum cooling.
After having installed the fan I have had no more problems with sticking fillament.
FreeCad original file included as well as printable STL files.