You can set the fan to run at 12v by soldering to a point on the mobo or by splicing it in to the dvd drive power. It's a 12v fan but ms has it run at 6v on idle / 8v in games. This can lead to overheating. Note: It will be pretty damn loud at 12v most are delta fans.
Also the cpu/gpu heatsink are held on by flexible x clamps which are terrible and can be replaced by metric screws/bolts thus making them much tighter and improving heat dissapation.
here is a guide for removing the xclamps w/ parts list
http://www.llamma.com/xbox360/repair/ring_of_light_x-clamp_fix.htm
Both of those issues lead to problems since the gpu/cpu chip are soldered in and not pin/socket type.
Basically when it gets too hot and then cools it leaves micro cracks in the (cheap) solder and when it gets bad enough you get RROD.
Obviously if you are going to change the x clamps on the heatsinks while you are in there I would replace the TIM with some artic silver 5 or something else thats good.
Basically it's gonna need some maintenance just like a PC. I'm sure its full of dust also. Dissasembly is actually very easy but you need a star type key, its like an allen key but in a star pattern. You can buy a kit on amazon cheap.
http://www.amazon.com/HDE-Xbox-Console-Opening-Tool/dp/9862510013/ref=sr_1_1?ie=UTF8&qid=1352516495&sr=8-1&keywords=360+opening+tool
the weird looking metal piece is to put in all the little divots in the back at once and pop the plastic off. and the piece jutting out of it is for popping off the side covers where the hd sits and the one on the other side.
Yea... I've fixed a few xbox's in my time
Edited by HardwareDecoder - 11/9/12 at 7:08pm