Loud fan noise

Question

Level 1

1 points

Loud fan noise

I have a five year old MacBook Pro. It had become slow and the fan makes a real noise intermittently. I went to a Genius Bar and they ran a diagnostic test that showed the hardware was ok so suggested that I reinstall the OS (El Capitan) and clear out the unwanted stuff. I've just completed that process, selectively reinstalled certain files from the TimeCapsule backup, but managed to clear Gb's worth of unwanted clutter. I have partial success in that the speed has improved but the fan is still very noisy. I've now run out of ideas. I was hoping that someone out there may have an idea as to why the fan is running at such a rate with so little going on comparatively processor wise. Are there any thoughts on how to reduce the fan noise? Suggestions would be greatly appreciated. Thank you.

Posted on Feb 7, 2016 10:03 AM

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Answer 1

Allan Jones

Level 9

68,696 points

Feb 7, 2016 10:19 AM in response to Biffob

An overactive fan can indicate a problem with a temperature sensor. There is a safety function in that, should the system detect a failed temp sensor, it tells the fans to run at full RPM to prevent heat damage, but resulting in a noisy computer.

A sensor problem can be detected with either Apple Hardware Test or Apple Diagnostics depending on your exact MBP model. Information on using these tools is in this Apple article:

Using Apple Diagnostics - Apple Support

If either reports an error with SNS" near the beginning, that indicates a sensor issue. However, there are more than temp sensors so posting the full code here may help to narrow it down.

If the computer passes that test, we'll need to walk you through some other diagnostic tests.

It would be helpful to know your exact MacBook Pro version. Please do "About this Mac" from your Apple menu and, in the resulting window, tell us what the line I have indicated with a red arrow reads on your computer:

For security reasons, do not post your serial number in either test or a screenshot.

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Answer 2

Biffob Author

Level 1

1 points

Feb 7, 2016 10:31 AM in response to Allan Jones

Thank you Allan. It reads - MacBook Pro (13-inch, Early 2011). I'll try running the diagnostics test you suggest and see what shows up. I hadn't before as the Genius guy ran some tests in-store that all appeared ok. Clearly not though, so anything you can suggest will be excellent. I'll run the test as soon as the Time Machine backup has completed. Thanks again.

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Answer 3

OGELTHORPE

Level 9

57,305 points

Feb 7, 2016 10:35 AM in response to Biffob

Take off the bottom plate of the MBP and see if there is dust an debris inside. If so, clean it out.

Ciao.

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Answer 4

Biffob Author

Level 1

1 points

Feb 8, 2016 1:25 AM in response to Allan Jones

Hi again Allan. So, I've run the Apple Hardware Test, I chose the extended test and the result was no trouble found. The test conducted by the Genius Bar person also produced that result. I also removed the back of the MBP to check for dust build ups as suggested by OGELTHORPE, There was a small amount of dust present that I removed, however the fan still runs very noisily. I'd be grateful for any other ideas you may have. Very much appreciated!

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Answer 5

Biffob Author

Level 1

1 points

Feb 8, 2016 1:26 AM in response to OGELTHORPE

Thanks for the suggestion. Unfortunately, despite there being some dust build up, this didn't work. Appreciate the idea though.

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