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macrumors member
Original poster
Mar 26, 2022
I just got an old 2008 Macbook 15" unibody MacBook Pro.
My problem is : it's overheating 30-40 mins after booting. It's very very hot inside, and the fans doesn't look to work very well.
I tried with Mac Fans , I can see the fans are always running 2000 rpm, but don't go more than this, and so it's overheating and freezing + I have to force shutdown.

What's wrong with this ? It looks like the Mac itself doesn't use well the fans, they always very slow.
And if I use Mac Fans and set to the maximal , I have no problem. But if I don't use it, I have overheating.
I can't explain

Any fix ?

Certificate of Excellence

macrumors 6502a
Feb 9, 2021
I wonder if your cpu/gpu heat sink sensor is malfunctioning? You can use Apple Hardware Test to check if your temperature sensors are working correctly. Reboot and hold down D to invoke the diagnostic partition/tools. If you don't have it, you can download the correct AHT from Here. If everything checks out, next step would be to open the MacBook up, clean out all the dust and gunk and clean/repaste the cpu/gpu heatsink. A video on how to do that is Here. Considering the age of these MacBooks, if this has never been done, it is entirely possible that a simple clean out/repaste could fix your issues.

Good luck.
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macrumors newbie
Dec 16, 2023
It's very very hot inside
This would suggest that the heatsinks are making good contact with the CPU and GPU. Are the heatsinks completely clear of dust? A "wall" of dust can block air from exiting the heatsinks.

Though I'd agree that something has happened to the temperature sensors.
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