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Which way around does a CPU fan go?


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#1 moeburn

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Posted 03 September 2013 - 23:03

Just detached my cpu fan from my cpu heatsink for the first time, to get at the really bad gunk in between.  Reattached them, but I think I might have it the wrong way around, because it sounds way different now.

 

One side is very dirty, and one side is very clean.  The very dirty side has the label on it.  Which way should be pointing at the CPU, the dirty side or the clean side?




#2 vcfan

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Posted 03 September 2013 - 23:13

alot of times it doesnt matter which way the fan goes, but just put it to blow air towards the heatsink if you're not sure. to tell which direction the air blows, look at the fan, there should be two arrows,one showing the direction of airflow, and another  one showing the rotation direction.



#3 Javik

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Posted 03 September 2013 - 23:14

Hold it in your hand then briefly power the machine on, if I ever mount a fan the wrong way around that usually helps me correct the issue pretty quickly.



#4 Hum

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Posted 03 September 2013 - 23:16

One side is very dirty, and one side is very clean.  The very dirty side has the label on it.  Which way should be pointing at the CPU, the dirty side or the clean side?

Why not CLEAN the fan ?



#5 TheExperiment

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Posted 03 September 2013 - 23:17

Just detached my cpu fan from my cpu heatsink for the first time, to get at the really bad gunk in between.  Reattached them, but I think I might have it the wrong way around, because it sounds way different now.

 

One side is very dirty, and one side is very clean.  The very dirty side has the label on it.  Which way should be pointing at the CPU, the dirty side or the clean side?

Typically they have small arrows somewhere on the casing telling which way the air goes.  It should go outward to not push heat towards sensitive components.



#6 OP moeburn

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Posted 03 September 2013 - 23:35

Why not CLEAN the fan ?

 

I tried.  It's that weird beige residue that dust leaves behind.  Like crude oil or something. It doesn't come off from vacuuming or wiping, and barely comes off with scraping.  It's not thick or anything, it's probably not adding so much weight that it slows the fan down.  

 

Thanks everyone!  I had it blowing air AWAY from the cpu accidentally.  Put it back to blow air towards the CPU, and it no longer sounds like a squealing monkey.  Yay!  

 

For anyone curious, the temperatures were about 5-8 degrees hotter blowing air away from the cpu, than they are blowing air towards the cpu.



#7 Enron

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Posted 03 September 2013 - 23:46

Thanks everyone!  I had it blowing air AWAY from the cpu accidentally.  Put it back to blow air towards the CPU, and it no longer sounds like a squealing monkey.  Yay!  

 

For anyone curious, the temperatures were about 5-8 degrees hotter blowing air away from the cpu, than they are blowing air towards the cpu.

 

You risk running out of air by doing that. Check atmospheric pressure.



#8 Andre S.

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Posted 03 September 2013 - 23:50

The reason it sounded like a squealing monkey, as you elegantly put it, is that it was so inefficient in that position that it had to spin at full speed constantly. A CPU fan usually spins relatively slowly which is what keeps it quiet.



#9 papercut2008uk

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Posted 04 September 2013 - 02:06

the thick gunk is from either someone smoking or incense/oils.

 

if you remove the CPU fan and heatsink, you need to reapply thermal paste, first removing the old stuff.

 

if you just remove the fan, the air should push into the heatsink, and ideally the fan should blow towards the back of the case if you have an exhaust fan or to the top if you PSU is the only exaust fan in the case, if you have an AMD CPU they usually only point either up or down, if it's an AMD heatsink you should position it with the exaust going up.

 

either have the fan side pointing towards the front of the case or the bottom of the case.

 

if it's just a stock fan it doesn't matter which way round it go's.



#10 thomastmc

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Posted 04 September 2013 - 02:28

In America/Europe, clockwise, but in Australia it goes counter clockwise :)



#11 Javik

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Posted 04 September 2013 - 14:32

If you get a pack of kitchen cleansing wipes (I usually use the dettol ones) those clean fan blades very effectively



#12 Aheer.R.S.

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Posted 04 September 2013 - 14:34

on the fan itself, label side up, (there might be a direction of airflow arrow on one of the sides, I usually set the fan to blow into the heatsink)



#13 Wakers

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Posted 04 September 2013 - 14:39

I'm really hoping the "thick gunk" he's talking about isn't the thermal paste...



#14 Mindovermaster

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Posted 04 September 2013 - 14:39

Actually, I've seen some that have the label on the wrong side. The side with the little wires are the outflow way.

 

papst_silent_case_fan.jpg

 

That way is outflow.



#15 OP moeburn

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Posted 04 September 2013 - 16:00

I'm really hoping the "thick gunk" he's talking about isn't the thermal paste...

 

I really hope you didn't put thermal paste between your fan and your heatsink...

 

I've taken off heatsink/fan combos and reapplied thermal paste on CPUs over a dozen times.  I know how to do that.  What I've never done before, is separate a fan from its heatsink.

 

The black gunk was the same stuff that had accumulated in the air filter on the front of the case (this case and cpu/fan were second hand from someone else).  They weren't a smoker.  It looks like crude oil, so thats what I call it.  They were Italian, however.  It may have been a combination of lots of dust, and the cooking oil fumes that permeated their entire house.

 

Didn't help that my fan actually had different labels on both sides.

 

The strange noise the fan was making when it was upside down was not the fan RPM increasing.  I use speedfan, and I checked when I heard the strange noise, and it was similar speeds.  It just didn't like being upside down, or maybe I didn't tighten the screws enough and it was slightly vibrating, or something.