Hey dashv!
I was happy to find your post since I'm fighting exactly the same issue with american PS3 Phat CECHA-01 which I purchased off ebay for the same purpose as you. It also never YLOD'ed before and surprisingly came with 1.50 official firmware. Before updating it to the latest available firmware from Sony I played a few PS3 games that were included in the lot. Right away I noticed that it sounded like a jet.
I started reading here and there and also found this method of removing IHS, etc. So I decided to do it. I purchased few painting knives (everyone says they're the best for the task and I concur after the successful job) and Arctic Silver MX4 compound. I also bought a couple of thermal pads from some Phobya brand (Thermal pad Ultra 5W/Mk). Unfortunately there were no 2mm neither 1,5 mm pads available at the store so I've settled with 1mm.
Firstly I've installed a CFW to look into the temperature readings. Here and further temps are in Celsius. I've noticed that CPU is much hotter than GPU (70-71 on idle vs 58 respectively). I also carried out few observations.
Some homebrew apps have means to control the system fan but I'm talking about the official system settings (a so-called syscon):
PS3 starts at what I believe is level 1. Just as CPU hits 66, I hear probably level 2. It still kinda comfortable. Then it goes to level 3 when CPU is around 71. GPU sits around 57-60 all the time. When I put some load on to it with PS3 game (e.g. Heavy Rain), CPU hits 74-75 and stays there. That's when the cooler goes to level 4. GPU is surprisingly still around 60 no matter the action on the screen.
So now is the process:
I disassembled the system completely and started working on removing the IHS. The process itself IMO just looks insanely hard. When you start working it's all really simple. I cut the silicone carefully and slowly with the painting knife (tbh, it was less scary than opening up the GPU).
GPU was also rather easy, albeit a bit scary: a bit of heat from wife's hair dryer and the cover came out with a help of butter knife. No extreme pressure or anything. I also used a piece of carton.
So now is the thermal compound. The whole my life I used the spreading method on all my PCs. It always worked perfectly and I even did some comparison tests. To me the spreading was always the winner.
But working on PS3 I've read a ton of material about how's the peasize drop method is better for PS3. So I did that both under and above the IHS. I've also replaced the stock thermal pads with mine (keeping the original for the time being). So the original are definitely thicker. I'd say they're 2mm or so (you can't find that info on the internetz btw, only some discussions about 5mm (!) thickness? lol). Anyways, those 1mm kind of look ok to me. After reassembly of heatsink they sit tight. Heatsink also leaves those markings that, I believe, signify the proper pressure applied. BUT! I'm not sure about that since I wasn't able to test it all out properly. And here's why:
After I've reassembled the system putting everything together, all the bits and screws, I've got the following result.
CPU is 69 and GPU is 65 on idle. As you can see, the GPU is almost 7 degrees hotter. The load is light (dynamic theme from Heavy Rain, few light render scenes). What's worse, the CPU starts to heat up more, reaching 73 - and that's on idle. Same with GPU. It never went over 60 before, but now it can reach 65 and go higher, I think.
I also can not put any proper load on it right now since I've probably messed up the assembly of the BD-Drive. No installed game can start, you just get a black screen. And the BD-Drive does not recognize the BD inside properly. I mean, it sees the disc inside and spins up, but does not tell the system it's loaded.
But what's interesting here is that the cooler won't go higher than level two. Even though the CPU is 73-74. It's also moving a lot more of hot air out of vents. So that's kind of... weird?? If I didn't have the CFW, I'd never noticed that something's wrong with the system (well, apart from BDDrive ofc
)
So why I'm writing all that now and not after the subsequent reassembly?
Well, now I'm wondering about thermal compound application method. Could you please elaborate more on plastic wrap? I was going to use my method of an old credit card to spread it but maybe yours is better? And I'm also sure that I should've cleaned the GPU's memory chips better. There is some of the old adhesive thermal paste left there. Did you also use the credit card to scrape it off? Not only from the main core, right?
Oh, and I also found some fancy thing specifically for the PS3 (and Xbox360): Coollaboratory Liquid MetalPad for PS3 and Xbox360. I've already purchased it. If you google it, you'll see that this is a some sort of ready-to-melt liquid metal thermal pad (?!) designed specifically for those game systems. They even put up a guide telling how to disassembly the system and apply those pads. To my understanding, they're compatible only with Phat ps3. I wonder shall I try using them or is it just a waste of time? I never heard about this brand nor about liquid metal thermal pads. I also can't find any reviews of them. Only some retarded article in German which was probably paid for anyway.