My extruder stepper kept overheating, so I made an adapter to hold a standard 40mm fan. Now I am able to reliably print overnight without jams. If you are not lucky enough to have your name start with an "A", print the A-less version. :) Screw your 40mm fan to the holder with washers as spacers (if required). Replace the front-most assembly screw with a spare longer one and use it to mount the fan holder. Keep it cool!