What causes this fan motor cage to fail?
 

Has anyone else had their fan motor cage break? What causes it? I was expecting to find something from the cabin filter area broke off that may have fell into the fan, but didn't see anything. Just want to make sure the new one doesn't break, not an east replacement. Never seen this happen on any car in the past, motor works fine. 2005 X5 with 200k miles.

feels like a case of plastic plus time. my guess is a slight bit of off-balance cause a little bit of wiggling in the bend or seem and eventually fatigue failure took off like a zipper

Is that a crack in the ring? If so, vibration over time broke the spokes.

The entire center of the fan is missing, broke off the hub.

I didn't realize poker whole side is broken off. Two squirrel cages on opposite sides of the motor