Sony VGN-Z diassembly

My laptop was overheating a lot, causing shutdown, so i cleaned the fan from dust and applied liquid metalpad on cpu, gpu, chipset. I ve noticed there is a big gap between heatsink and all chips. I only know that originally there was a thermal pad between mobo chipset (idk, it may be discrete gpu) and a thick thermal paste layer on nvidia gpu and intel cpu, but didnt think that even after replacing thermal pad with a 0,5 copper shim there still is a noticeable gap and heatsink is staggering. I added one more 0,4 copper shim on the nvidia gpu to make heatsink more stable and reassembled laptop. This solution worked, my pc didnt shut down even after some occt cpu tests. But then, after a week i was need to deattach motherboard again (without deattaching heatsink from it). Unfortunately, the overheating issue has come back. So, i m planning to disassemble it one more time, but now i will add one more copper shim on cpu, change copper shims with thicker ones. What do u think? Will it help? What thickness should i use? Was there originally so big gaps?

 

Until somebody answers this -
did you find a good instruction or YouTube video how to disassemble the VGN-Z to do this? Might give it a try once I find a bit time.. but not within next few days

 

Yes, i ve read official disassembly guide http://totktonada.ru/doc/VAIO_Z/vaio-z.html , then watched , and finally read this http://rdaemons.blogspot.com/2010/09/how-to-clean-heatsink-and-renew-thermal.html
So, if u only need to change thermal compounds on motherboard skip on "<Main Section >
* MS-1-D. Disassembly" pages 9, 16, 23 - 27, 28 (no need to remove the battery, just disconnect it from motherboard), 31, 32, 34 - 40, 44, 45 (2-4 step), 46, 47 (2-4), 48 - 51, 53, 57 to the end. But dont skip 6th page! In the video and blog they forgot to mention the concave part.
Also, be careful with stamina - speed ribbon cable (located on the top of middle frame). It can be easily broken.
I suggest u to deattach screen, its only 2 screws, but after that u can take out the motherboard with power cable.
Finally, sony might do some changes in official guide. For example, it shows there are thermal pads on cpu and nvidia gpu, but a lot of vgn-z owners have only thermal paste.