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T400 Overheating - caused by dried thermal grease & dirty fan



I have a Thinkpad T400 bought it brand new in 2008, fully optioned with a t9600 processor. I've since then removed the obsolete Vista x64 and replaced it with Win7 x64. Replaced 7200 160gb hdd with Intel 160gb SSD. Upgraded 4GB of RAM to 8GB of RAM.


The problem I am having is random overheating. Every once in a while it will just shut down, I've taken a infrared thermometer to the bottom of the unit and measured ~163 F surface temps!!

I've had TPFanControl installed since the vista days (my warranty had just expired by then), as I had experienced some overheating issues.  I installed Windows 7 and it seemed to run much cooler...but recently I am having issues again.


TPFanControl shows 62C and dropping at the moment (now it's 59C), but it was reading 73C+ before I switched fan control to manual. The fan speed is now at 3422RPM instead of the ~2000RPM it was reading before (at 73C).



Removed palmrest, keyboard, and keyboard bezel, followed by the  fan & heatsink

Watch the training T410 videos for each component on Lenovo's service training site here (T400 is similar)


Blew out what  dust there was, and then removed the fan assembly.


(example photo of T series Thinkpad with accumulation of dust in the fan)




Thermal paste was splotchy at best, most of it was around the sides of the cores....lots of the CPU core was bare.

Cleaned with alcohol and applied thin even layer of Arctic Silver 5 across GPU and CPU cores.


Now running at 42C with integrated graphics enabled. With ATI HD3470 enabled, both CPU and GPU are registering at 46C and holding steady (BIOS controlling the fan). Before the CPU was at 73C while the GPU was around 50C....


Following this preventative maintenance, I find that the fan is actually ramping up and the power management software is able to manage system temp without resorting to throttling the CPU.  It got as high as 59C (evenly distributed across gpu and cpu).


After a minute or two, it has dropped back down to 46C.

This was observed with power manager CPU set to "High Performance."

With CPU set to "Adaptive", idle temp is 34C.


I recommend it to anyone with the know how, and if your laptop is out of warranty.




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NateS On 2014-01-17, 2:11 AM
Post moved to a new thread in T400 / T500 and newer T series ThinkPad Laptops

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