Asus ROG laptop GPU fan making rattling noise all of a sudden

[hellshoot]

I've a 5 years old Asus ROG G750JZ and everything was working great until yesterday.

Yesterday morning I boot up a game and fans were working as espected, after lunch I leave for a meeting and fans were doing their normal noise until I turned off the laptop around 20:30 (8:30pm). Then I drive back home (1 hour trip) and when I turn on the laptop, around 22:30 (10:30pm) the GPU fan starts to make a lot of noise. It was not the normal expelling hot air noise from a silent fan, it sounded mechanical for some reason.

I fully disassembled my laptop and cleaned all the dust, which was not that much for a 5 years old laptop. I checked the fans and they were rotating well with no resistance or obstructions and it doesn't look like it's off balance.

I can't figure out why it's making a rattling sound and would gladly appreciate any help given.

My specs:
Asus G750JZ
CPU: Intel i7-4700HQ @2.40GHz
RAM: 16 GB DDR3L SDRAM
GPU: NVIDIA® GeForce® GTX880M 4GB GDDR5

The seemingly faulty fan is an ADDA model AB08812HX26DB00 with the references 00G750JH and 43UG.
ADDA fan making the noise.

 

[jay32267]

Sometimes fans will spin free really nice when they are not under power, but when power is applied and the magnetic forces kick in, the bearings are put under different stresses and don't run in the races like they are supposed to and noise may occur.

 

[hellshoot]

I thought about that but wasn't sure if that was the case. Would it be possible to fix something like that or is a total replacement the best option?

 

[jay32267]

If the bearings are going bad, they can't really be fixed, so you would have to replace the fan. I have no idea how difficult that is, or if it's even a reasonable thing to do, in your situation.

But, I have definitely come across fans that spin real nice when you spin them by hand, and then they make a hell of a racket when you power them up....so it's not uncommon.