Reduce Loud Rattling sony vaio CS fan noise

Update: 3 months since my post on reducing the fan noise. The noise seems to reappear. I took apart my vaio CS again to peep inside and try to figure out what exactly is the problem. I found that there is a lot of wobble when the fan rotates which makes the blades to brush the edges. So i came up with this.
Take a smooth surfaced plastic washer and stick it to the base of the center rod in the fans, like this in the photo. Look at the arrows to see how the washer is stuck to the base of the fan. After this put everything back as before. Now the fan noise is very minimal as the wobbling reduces to a great extent and the fan runs smoothly. For full article look below.

                                                                 

Hi it has been nearly 10 months since i started using vaio CS17G, it is an excellent laptop running vista without problems thus far. But since yesterday i started getting a strange loud fan noise all of a sudden.
I could follow the temp readings and the noise came on as soon as the temp was nearing 50C.
After googling for a while i learnt that this is a common problem with the sony laptops and was attributed to the faulty fans manufactured in china which were used by sony for their laptops.
I could go for repairs from sony under warranty, but for many people the problem returned after the repairs.
Since i had also partitioned the hard disk and installed ubuntu, i was not sure of warranty.
So i decided i will fix this on my own.
So these are the steps to reach the fan and fix the problem.

1. Disconnect power cable after shutdown and remove battery.
3. Remove the screws from the bottom of the panel after turning the laptop over. Will need  to remove almost 15 screws, that was the case with my CS17G.
4. Pull out the DVD drive.
5. Remove the panel covering the hard disk
6. Remove the black static cover over the Hard disk by removing the 3 screws.
7. Pull the hard disk out.
8. Remove the 3 large screws from the bottom of the black casing you will see after removing the battery.
9. Now you should be able to pull the panel out. Be careful to detach a cable near the RAMs.

This pic shows the unit after the panel is removed. All of that coppery thing seen is the fan unit.

            9. Remove the 6 screws that attach the HSF (Heat Sink Fan) unit to the mother board and disconnect the cable attaching the HSF to mother board.
           10. Now it is easy to take out the fan unit (HSF). You need to take a lot of care while doing this because of the thermal paste which is present between the copper panel and the CPU.

             
        













 
    
           11. Now remove the 4 screws holding the unit together.
           12. Its a magnet run fan. Remove the blade unit.

               










   

13. What i found after examining the fan was that the fan blades were brushing the ridges over the circles left behind on the black cover in which the fan runs. See the arrows in the pictures.

 

     15. I had to file these ridges smooth and a drop of oil in the hole to reduce fricton.

     16. Also the blades were brushing the copper panel. So i bent it to take it away from the fan blades, So that it does not touch the panel while rotating.

     17. Put everything back in reverse order.

This reduced the loud noise that was coming out of my laptop by more that 95%.

Its been 2 days since, and no much noise.

The cause of the fan noise could be anything from loose fragments in the fan, fan blades brushing the copper cover borders or the plastic cover bordes or the uneveness of any of the components.

I am just illustrating how to remove components and reach the fan.

Once you reach the fan, inspect it carefully and find out where the fault lies and rectify the same.

Do this only if you are confident and not worried about loosing the warranty, AT YOUR OWN RISK.