I recently used a can of compressed air to clear my laptop's air vents from dust and other dirt that accumulated over time. While doing so, I did not hold the CPU fan in place in order to stop it from spinning as a result of the inwards air flow.
Now, when the machine is powered on, I can clearly hear a rattling noise coming from the CPU fan. There is no noticeable increase in CPU temperature as far as I can tell. Besides the noise, it seems to work perfectly fine even under heavy load.
I'm interested in the technical explanation for what is happening and why it is happening. Also, is this a problem that can/should be fixed without getting a replacement fan?
The noise is actually most noticeable when the machine is idling (i.e. when the fan is spinning at a moderate speed). As the fan speeds up under heavy CPU load, the rattling noise does not really increase in loudness, only in frequency and tone. I haven't had the chance to open it up yet, so all ideas are still welcome.
I finally got around to taking a closer look, this is what I found:
It looked pretty bad, but the problem still persists after thoroughly cleaning the fan. Any other ideas? I'm about to order a replacement fan.