98 Civic Heater Blower Fan Noise

My '98 civic will be humming along with the blower fan on and all of a sudden it will make a gawd-awful noise like something is stuck in the fan.
I pulled the fan and operated it out of its housing and it seemed to be OK, with no noise and no noticeable wobbling or imbalance.
Any ideas?
Thanks, Dennis
doregan at verizon dot net
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.