So my MBP has been struggling recently, getting hot, fans going silly etc. I decided to open it us and have to admit I'm slightly ashamed I didn't do it earlier. My mac's been in for service so many times I guess I lost track of how long it has been since it was last in. So, I opened it up and got rid of all the dust I could, gave the fans a good blast, seems to be considerably better. I'm considering applying some better thermal paste now I'm out of warranty, but that's for another thread. My main problem is the left hand fan (when looking down on the laptop) still seems to produce a slightly more electronic sounding buzz, rather than just the standard noise of the airflow. This seems to be going on even when the fans are barely running, if at all for the right one. Any idea what might be causing this or what a possible fix might be? If it makes any difference it seems to be consistent regardless of the orientation of the laptop. Thanks for any tips you can give.