I have a 2014 MBP, running very well but for one issue: the fan doesn't seem to move any air around, even though I can hear it running. As a result, the laptop gets quite warm, and further, it seems that the Mac throttles the CPUs to keep it from overheating (performance is one reason I got it in the first place).

I can hear the fan running (well, a fan-like noise anyway!) and the noise builds up when the load increases. I installed smcFanControl, and it shows the temperature and fan speed changing as expected. But no air movement. Running something like htop from the terminal shows CPU usage topping out at 60-70%. The CPU tends to sit around 60-70 deg C, which seems quite high for a permanent state. Letting in January cold air through the window only makes minimal difference.

What I tried:

  • I restarted the SMC
  • I opened the cover and looked for any lint. What very little there was, I removed, but there was no significant build-up in the vents or around the components
  • I installed smcFanControl to see if I can tune the fan speed, the noise does respond to the settings but again, no air flow

None of it made any difference.

Any idea what the problem is, and how I can fix it? The laptop is working very well, so I'd rather keep it than replace it, even though it is getting old. Would Apple help at all - I never had anything fixed with them, but ofc the Mac is out of warranty.

I think the problem may have started around High Sierra upgrade, but it didn't bother me much at the time.


It was suggested that this question is relevant. But I don't think so. I did clean the inside, and found no obvious sources of lint. Perhaps applying thermal paste would help, but I cannot see how, if the air is not pushed around by the fan.

  • When was it last stripped & cleaned? If the answer is 'never' then that's your next port of call. – Tetsujin Jan 14 '20 at 11:59
  • Well, I opened it and gently cleaned it today, but I didn't move any parts other than the bottom cover... is that what you mean? – Bennet Jan 14 '20 at 12:23
  • You really need to get into the airflow, which can often get blocked by dust at the exits. At minimum, blow back through it the opposite way to the usual airflow, at best, strip it far enough that you can see it all exposed & be able to brush it out. – Tetsujin Jan 14 '20 at 12:24
  • I couldn't see any obstruction in the airflow ducts, even with the cover off. I blew some compressed air, though admittedly only in the normal direction. – Bennet Jan 14 '20 at 12:26
  • 3
    Does this answer your question? Serious Performance Problems using Expose in Catalina – anki Jan 14 '20 at 13:42

How are you so sure that there is no air being moved around?

Further, when does the throttling apply - right at the start or after some time? Because at some point under high load, you will experience some throttling on basically any laptop.

The only thing - depends on how familiar you are with such things - I can think of, is taking the back cover off and literally looking at the parts. Yet, I would not necessarily recommend this.

Before doing something like this: Save your data either in a backup or by copying your files.

Apple might be able to help you, but what usually do and recommend is going to a certified repair shop. It's more personal and you usually speak directly to the repair guy. Though, I guess they will probably not be able to do anything different than what you did, @Tetsujin or I suggested.

  • Hi X_841, I feel no airflow at all around any of the vents, on my hand or on my cheek - and as someone who did CPR training I know what even faint air movement feels like :) the throttling is pretty much immediate, at no point recently has my Mac been running at 100% CPU or even close. I looked under the cover, but there was no significant amount of lint. The little there was I cleaned away, to no avail. – Bennet Jan 14 '20 at 12:25
  • Ok, very interesting. Have you tried to run Diagnostics on the machine? And maybe have a look at single user mode/startup modes (support.apple.com/en-us/HT201255). You should definitely get a CPU usage over 100%. What are you running on it? One program that (on my machine) ALWAYS uses all the CPU power is HandBrake (encoding videos). – X_841 Jan 14 '20 at 12:30
  • I'll try the diagnostics. As for what I'm running, I'm a software engineers, so plenty of ways to try and squeeze full capacity out of the CPU. – Bennet Jan 14 '20 at 14:06
  • I think this is the right answer. @Bennet - I can't feel air moving on my hand or cheek either on my 2014 MBP - it is just how it (or my skin) is. Take the back off and turn it on and look. If the fans are turning and it is clean then that is all you can do. When closed, if you felt cold air blowing out when CPU was under load it might indicate bad thermal paste. Feeling no air just means you can't feel it. – lx07 Jan 14 '20 at 20:34
  • I currently only have access to my MacBook Pro 15" from 2017, which is obviously a different machine. I can feel a slight air flow on this side/bottom, where the air flows into the machine. I think you can feel the airflow, but I would not rely on it. – X_841 Jan 14 '20 at 21:32

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