CPU fan - which way up?

Hi folks,

I'm trying to work out which is the correct way up for a CPU fan. I don't seem to have any documention and the information I've found on the 'net seems a bit variable. It's a BS601012H and here are a couple of pictures that are on the 'net:

http://www.bluesmoke.net/Reviews/Hardware/arkua_6149/front_big.jpg
http://store.thermalfx.com/merchant2/graphics/00000001/BS601012H.jpg

According to some places, the heatsink can affect which way the fan should go so I've added a picture of the heatsink.

Thanks guys!

 

The fan should blow air towards the heatsink. Most fans have 2 arrows on the side, one indicating the direction the blades turn, and another indicating which way the air will flow.

E

 

Also, there should be plastic 'guards' over the top of the fan. They should be showing face up.

 

Not all fans have the guards.... but the fan should blow down onto the heat sink as stated above by Mr. Fred. The side that goes up (or faces away from the heat sink) usually has the brand name sticker on it, and the bottom (the side that faces the heat sink) will have 2 or 3 plastic arms that run from the outside square frame edges to the center to hold the fan motor.... some Intel fans have the plastic arms on the top, but the sticker is on the top too, so there's no confusion.