I watch a lot of youtube video etc and my MBA heats up as expected. However, the fan used to come on when doing this and now it doesn't. Hasn't come on for a couple of months. Is there a problem?
The fans will only come on when a processor intensive application begins to really take the CPU/GPU and thus the fans come on to compensate. It's unlikely that your fan doesn't work at all, nor should it always come on during YouTube usage (mine doesn't).
If the fan never came on the machine would get extremely hot and ultimately shut down. However, if you believe that your fan is not working, you can run the AHT (Apple Hardware Test) diagnostics that came with your computer or take the machine to a local service provider to have them run diagnostics.
The fans will only come on when a processor intensive application begins to really take the CPU/GPU and thus the fans come on to compensate. It's unlikely that your fan doesn't work at all, nor should it always come on during YouTube usage (mine doesn't).
If the fan never came on the machine would get extremely hot and ultimately shut down. However, if you believe that your fan is not working, you can run the AHT (Apple Hardware Test) diagnostics that came with your computer or take the machine to a local service provider to have them run diagnostics.
The fan, technically, is always on. From the moment you startup the machine, the fan is always running at about 2000 RPM. The fan will "ramp up" anywhere between about 2000 and upwards of 6200 RPM.
If you open multiple YouTube videos (tabs in Safari), let them stream for 5-10 minutes. From my experience, the fan became audible around 3000 RPM if a low noise environment. With multiple YouTube videos running (simultaneously) on the MBA for 10-15 minutes the fan should definitely kick in and you should hear it. Otherwise the machine would get incredibly hot, after a good 20-30 minutes of letting these videos run the machine would more than likely shut down to protect the processor if the heat threshold was exceeded.
If you really want to tax the machine, open each YouTube video in a new Safari window and then have all the windows visible via Expose.
I would add this: go grab iStat nano widget and watch the fan speed. Should be running around 2000 most of the time. If it reads zero then your fan may be stuck (mine has gotten stuck a couple of times). This is bad. If it reads zero GENTLY tap the right side a couple of times (gentle but sharp). That has gotten the fan unstuck before. But don't over do it.
