There was another thread about this. It looks like the factory fan can't be removed without removing the soldering welds holding the top part of the cooler on. So, it can likely be done but not without some custom modification.
I sent a note to Andy LeMont, and he sent me back the following:
Fan is rated for MTBF 50,000 Hrs and a 2 ball fan. Most
of the failures associated with fans is due to bearing
failure (99%) This is a high quality fan I paid a $1.30
extra per fan for the added reliability. 5 failures per
100,000 units in that 50,000 hrs time span would be
about what I would expect. I am still working the
warranty details with my Atty. But essentially I will
replace any heat sink in which the failure is bearing
related. If (fans die because they're shorted out), I will stock
replacement fans from my supplier.
I somehow don't think that would work as well as it seems. The Glaciator was designed to have the fan where it is. If you tried putting the fan on top like most heatsinks, it would mess with the cone vortex of the fan and create more noise. You see where I'm going with this? Besides, with as High quality as the fan is I doubt that it will die anywhere in the near future. Just make sure to keep the dust out of it and you should be fine.
Andy's offer to replace any heatsink in which the fan failed is generous but how much time do you think you would have to realize the fan had failed before you CPU went up in smoke? I know its only a few seconds if CPU is bare. Maybe with a heatsink only and good case airflow it might last longer? I have no idea. My Epox 8K7A mb has a BIOS setting which enables it to shudown the PC at the specified temp which can be set between 60-100C.
After seeing 57C temps with my Tbird 1.2 and a generic cooler I ordered a Glaciator yesterday. Can't wait to get it!
Starting out at 21.3C and the CPU idling w/halt-on-idle, after 10 minutes, my 1.0G/266 running 1.5G @ 1.95V was up to 31C. Doing the same thing running Prime95 Torture. Starting at 34C, in 5 minutes, it was up to 59C. If you are worried about a fan failure while your PC is unattended, get that program ( forget the name) that will shutdown your PC if the in-socket thermistor detects a temperature above whatever value you choose to specify.
I just received a couple of these heatsinks today. I am examining one of them closely. It is too bad they decided to weld it right where they did. Otherwise it looks like it would have been pretty straightforward to service or replace the fan. I must say the fan appears to be very sturdy.