Right above where the CPU heatsink fan blows out, there is a grill / 80mm fan area on the side panel of the case.
 
If I were to a fan there, should it blow out of the case, or towards the heatsink?
 
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Also, I'm not sure about how fans blow, because if I put my hand over the fan, it seems to be blowing on both sides lol
 
Example: http://en.wikipedia.org/wiki/Image:IMG_1549.JPG
 
This fan would blow air upwards, correct? Generally the "sticks" mean air flows out on that side, right?

it should blow OUT of the case if the cpu fan is blowing "up" . Their is a cooler that is designed to blow "down onto the cpu, in which case the side fan should pull air in, but must fans blow away from the cpu.

 
It's a stock AMD cooler, what type is that? Blow outwards towards the side panel?
 
So I should put my side case fan blowing out of the case, yes?
 

dells blow in reverse
 
some computers suck air in, sealed dells do that - its an old design
 
its been proven time and time again you blow air through a cpu cooler - there are many reasons - such as as dust builds, better cooling etc

The inlet grill in the side panel is designed to allow cool air into the case, it is not normally used to exhaust air. Standard OEM heatsink design blows air down over the heatsink towards the motherboard, normally aiding in cooling CPU power circuitry. The side inlet grill frequently has an adjustable air guide on it to aid in supplying cool air directly to the cpu cooler, theoretically increasing its cooling efficiency.
 
Air flow and fan rotation is normally indicated by two arrows on the frame of the fan, sometimes these are difficult to find.

Two rules of thumb:
 
1. Heat is better dissipated from a heat sync in an environment with POSITIVE pressure.
 
2. With the right amount of fans blowing air INTO the case, and only a few exhausting air slowly, ANY air hitting the CPU cooler or fan will create enough turbulence in that positive pressured environment, to disspitae heat properly and effectively. However a linear flow is best rather than a high turbulence flow if possible.

 
Positive pressure? Turbulence? Hmm?
 
For specifics, this is what I have:
- AMD X2 3800+ w/ stock heatsink fan
 
- RaidMax xB 528BP Mid-tower
http://www.newegg.com/Product/Prod [...] &Tpk=528BP

 
- MASSCOOL FD08025B1M3/4 80mm Case Fan
http://www.newegg.com/Product/Prod [...] 6835150053

 
Hmm, in finding these pictures, I think I answered my own question heh. I have the fan like it is in the case picture above (the "curved" side of the fan fins facing the inside of the case.) Hehe