If you do indeed end up with YLOD, there is a simple way that might help you get it up and running, at least temporarily, and you dont have to open the system in any way.
First vacuum the system, then take a hair dryer, put it on hottest setting, and blow it into the vents for 10-15 minutes while moving it back and forth across the vents, dont keep it static. This fixed my fat PS3 YLOD, at least long enough for me to be able to transfer the data to my new ps3 slim. I still had 2 weeks left on my manufacturers flaw warranty provided the void sticker is intact (a swedish consumer law) so i sent it in explaining the YLOD. I was sent a brand new replacement fatty within a couple of weeks. So i dont know how long this simple fix would have worked, but it worked long enough to retrieve all the data, which took several hours copying the harddrive. The professional YLOD fixes people offer online are very unreliable according to themselves, so not really worth it.
Worth to keep in mind, should it suddenly die and you still have the ps3 you just bought. Keeping it vertical also helps with less heat buildup. External fan systems might also help.