If your old or newer Macbook Pro runs hot with both cooling fans engaged almost at all times then its most likely clugged by dust internally. In addition to dusting off the internals the factory heatsink thermal paste may need to be replaced. Both are very easy and quick tasks with good results. After both are done the idle and normal use temperatures will drop down to factory levels. I saw a decent drop in idle CPU temperature, with no change in 100% heavy load use. The recovery also seems much quicker and the fan duty cycles are less frequent. I have done this on my mid 2012 Macbook Pro, which showed typical signs of overheating resulting in CPU throttling. After cleaning up and thermal paste fix it feels like brand new again. The process is very easy, inexpensive, and quick.
Warning: performing this fix will most likely void the warranty!
- precision screwdrivers specific for Macbook Pro use
- coffee filter
- 90% isopropyl alcohol
- something with a flat edge (credit card, rasor blade, etc.)
- new thermal paste
Time to Complete
Pre Cleaning Temperatures
To gauge how well this fix works you can run a pre and post fix stress test with temperature stats collection.
Temperature stats monitoring and collection can be done with the Intel Power Gadget tool.
If you don't have
htop install it:
brew install htop
To perform a stress test and to saturate each one of the multithreaded 4 cores start 8 instances of the following:
/usr/bin/yes > /dev/null &
/usr/bin/yes > /dev/null &  44796 /usr/bin/yes > /dev/null &  44814 /usr/bin/yes > /dev/null &  44832 /usr/bin/yes > /dev/null &  44850 /usr/bin/yes > /dev/null &  44868 /usr/bin/yes > /dev/null &  44886 /usr/bin/yes > /dev/null &  44904 /usr/bin/yes > /dev/null &  44922
Open another terminal window and watch all 8 cores getting saturated to 100% with
htop showing all 8 cores at 100% load
Let it run for enough time to warm things up internally.
Once the temperature tops out note it down and kill the
killall yes  Terminated: 15 /usr/bin/yes > /dev/null  Terminated: 15 /usr/bin/yes > /dev/null  Terminated: 15 /usr/bin/yes > /dev/null  Terminated: 15 /usr/bin/yes > /dev/null  Terminated: 15 /usr/bin/yes > /dev/null  Terminated: 15 /usr/bin/yes > /dev/null - Terminated: 15 /usr/bin/yes > /dev/null + Terminated: 15 /usr/bin/yes > /dev/null
Open the Case
Here's a great and very detailed guide on how to properly and safely disassamble the Macbook Pro to access the fans and heatsinks: MacBook Pro 15" Retina Display Late 2013 Repair
Disconnect the battery from the motherboard
Clean the Dust
After removing the heatinks gently blow off the dust from the motherboard and both heatsinks. I used a large compressor in my garage with a air cleaning attachement but a compressed air can or vacuum cleaner will do as well. Any stubborn dust can be dealth with by using a gentle brush.
Dust inside on the back cover
Dusty Heatink Fins
Dusty Heatink Fins
Little room to breath
Clogged air intake
Fix the Thermal Paste
With both heatsinks off, using a paper towel or a piece of rug soaked in 90% alcohol clean all of the old thermal paste residue from the heatsink surfaces as well as the motherboard chips. Just make sure not to get the chips too wet. 90% will evaporate quickly but still too much may not be a good idea.
Once everything is clean, wipe everything off with a coffee filter. They don't leave paper fibers behind and will pick up any of those left on the surface.
Next, apply a small bead of the fresh thermal paste to the surface of the chips. A bead the size of a grain of rice is a good starting point. Using a flat edge tool spread the thermal paste evenly across the surface of the chips. THe layer should even, without hills or breaks, and not thicker than 2 or 3 sheets of paper stacked.
Carefully drop of the heatsinks back in place. Optionally wiggle them just a tiny bit to help the paste even out even more. Screw the heatsinks back to the motherboard.
Factory applied CPU thermal paste
CPU cleaned up
GPU cleaned up
New thermal paste applied
Reattach the battery and put the cover back on.