PS3 fan running at Mach 2 since day one after 2 to 3 minutes, even in menu, What up?

From the day I turned my PS3 40GB on the first time, the fan would blow at Mach 2 after 2 - 3 minutes even if it is only in the menu. From day one it's been in a well ventilated spot out of direct sunlight far from any heat sources. As I have been a gamer on PC, PS2 and XBOX I know to have it in a well ventilated space. The air coming out the back isn't hot at all but it doesn't seem to matter. Problem? What to do? CPU cooler maybe not well fitted?