Layer of dust in CPU fan

Eventhough I replaced my old PSU my machine continues to make this ungodly rumbling sound, leading me to believe it's either my CPU fan or rear case fan. I have it running without its cover now and I can tell the sound is coming from the back, but not which fan its coming from.

I shined a flashlight on my CPU fan and discovered a goodly layer of dust on the slats behind the spinning blades. Could this be contributing to my CPU's elevated temp (52º C) when running with a load? Would I have to remove the fan to get the dust out, or could I just use my compressed air to blow it out? Also could this layer of dust be contributing to the rumbling sound?

Is it OK to just leave the cover off so my machine can be cooled down? I keep the area around the machine fairly clean.

 

To take out the guesswork, take off your HSF, take the fan off and blow the whole thing out. I haven't heard of dust making a fan noisier but it makes sense it could raise temps.

But first, unplug your case fan and see if the noise goes away - i.e. find the culprit.

I had a PSU cause an ungodly rattle once even though there was nothing wrong with the fan inside it. Sometimes, I cut small pieces of thin, wide rubber bands and put the case fan screws thru them to create shock absorbers for the case fans. Not for the cpu fan though. I also lay a wide thin rubber band between the bottom edge of the PSU where it meets the case.

It also may be possible that one of your fans is about to "buy it ".

 

Can't I just blow the dust out without detatching my CPU fan? It was hell to get on the first time and I don't have any Arctic Silver to put back on if I take it off.

 

Yes. That's no different that blowing out your motherboard. There's nothing you can do about the dust that blows all over your case.

 

Would there be any harm in just leaving the cover off permanently? My CPU and system temp are WAY down without the cover on. If I left the cover off, could I unplug my case fans? I'd be very careful not to spill food or pop into it and I could blow dust out a lot easier without the cover on.

 

Hi shadowhawk.

A couple of words on that temp.

I would be sure the power supply fan is blowing out of the case and not pulling air in. If it is pulling air into the case I would take the power supply out, pop the cover and turn the fan around. Be sure the case fan is pulling air into the case and not blowing out. If you have two case fans, I would have both of the pulling air into the case. Let the PSU fan and the case openings expel the air. It should cool things down considerably. I usually tape closed the louvers in the rear of the PSU if there are any so the bottom louvers of the PSU pull hot air directly off the CPU. This only works if you have louvers in the bottom center of the PSU.

A lot of people have two fans either blowing out or pulling in and they just negate each other. Also, you can mount the floppy in the upper tray and leave the bottom open (without the cover) and it will cool down the hard drive quite a bit. Opens a nice air channel if needed.

Hope this helps.

 

The bottom fan on the PSU is an air intake fan and the rear one is the exhaust fan. Every site I've been to says to have a front fan doing air intake and a rear fan doing exhaust. You're saying that this is incorrent?

 

Front fans: intake
Rear fans: exhaust
End of story.

The goal is to move air through the case from front to back. Leaving your cover off is not the ideal way to run your box as this negates all your intended airflow. If it improves your temps, it probably means you could improve your fan setup in some fashion. On a "good" setup, taking the cover can actually increase temps.

What cpu and what HSF are you using? Stock coolers are notorious for simply providing the minimal acceptable level of cooling. Which may not be that great if you're a gamer. Do you have a small, cluttered case? Or a full-tower with just one intake and one exhaust fan? Just some thoughts. If you have good case fans, throwing about $30 at a good HSF (with Arctic Silver III) will usually tame your cpu temp problems.

Keep in mind that cpu temps reported by your bios or software can only be used for reference. In other words, can only be used to see if changes you make help or hinder. There is no guarantee the temp reported is anywhere near "reality ". So if your temps are reported high but your machine runs like a dream, then you may be worrying about nothing.

 

Chiles4 wrote:

My CPU is listed in my sig. I have a Millenium Glaciator HSF, which cost me $40 when I got it. It came with a packet of Arctic Silver. I have a full tower with one front intake fan, one rear fan, the PSU has an intake fan on the bottom and then blows air out the back. Could be that my old Glaciator has seen its day.

 

Hi.

The point was not to have two fans blowing out or two fans blowing in. They take air from each other and make each fan work harder and the air flow is almost nil. You'd be surprised how many systems are set up this way.

There was a time when the psu makers made their fans blow into the case. A lot of people still have those psu's but most have turned the fan around. The worse was those with a fan in the bottom of the psu blowing down and vents in the back of the psu. The fan just rotated the air in the case sucking in the back vents and blowing down into the case.

Most front case fans don't have a good path to get air because of the front of the case. You have a psu fan blowing out and a back case fan blowing out. There usually isn't enough air from the partially blocked front case fan to supply two other fans blowing out and you get less air flow. Taking the cover off the other floppy opening allows air for those two back fans. Works great.

Hey, just turn fans off or on or reverse the case fans one at a time and see what it does to the temp. Easy to find out.

Forgot. . . . . Shadowhawk you're absolutely correct. That was what I was saying. I've seen setups that actually created close to a vacuum inside a case. Makes my hair hurt. I worked on one system that had eight fans mounted on a plastic side and no cpu hs/fan.

The amount of air flow out of a case should be equaled by airflow into a case. The case openings will affect this. And, since the power supply unit generates heat, that rear mounted fan should be blowing out. Thats the starting point.

 

My PSU has a fan on the bottom but it pulls air out.

 

Hi.

If your psu fan is on the bottom and the psu has vents in the back then that fan is probably sending half the hot air out the back of the case and the other half back into the case out the rear vents of the psu. I would consider taping those rear vents closed with something like duct tape so ALL the hot air is expelled out the back of the case. This will cool down the psu more also. This is a common fix. Just check your temps. Easy to take the tape off if you don't like it.

Giles

 

The PSU has a fan in the back, not just a vent. The bottom fan is intake, the rear is output. If I were to duct tape the PSU fan, that would overheat the PSU.

 

shadowhawk,
A couple of weeks ago I was having a terrible time with BSOD's and I was sure it was a virus or a hard drive problem. I always run with the side off and don't have any problems except maybe a little more dust than if you didn't. I was having the same terrible rattling noise and had lived with it for some time. Shut down and reached in to feel the heat sink and you couldn't even touch it. Changed the heat sink to a taller one and replaced the fan. Immediately the problems went away. I understand what you mean about the fan being hard to get to, I have to remove my power supply to get at it. If the fan is rattling it's probably getting bad. Dust out of the fins will make a considerable difference but I would replace the fan. Good luck, Steve.

 

I've already decided I'm gonna get a new HSF. This one went through the brownouts and I think it was scathed.

edit: Would this fan do? It's listed as compatible with Athlon XP, MP and Duron. Would it work with a plain Athlon Tbird?

 

Hi.

The rear of the power supply unit is towards the front of the case. That's where the louvers would be. If you have a bottom and front fan on the psu then the suggestion doesn't apply.

 

Here is a nice tutorial page of what Giles and others are correctly saying about fans and their placement and orientation.

http://www.heatsink-guide.com/casecool.htm

Also, a good dust removal effort every 2-3 months will further help in keeping things in top running condition

Daddad

 

I put a new HSF on my CPU because I believe that's what was making the noise. My system is now running at 57º C with my email program, web browser, antivirus, firewall, hardware temp monitor and power supply software on. The system temp is 28º C which is quite cool. I'm still hearing the rumbling noise after replacing the PSU and HSF and running the machine without its rear case fan on. I honestly can't think of antying else it could be.

Is 57º C OK for CPU temp, or is it too hot?

 

Check to see if everything in the computer is tightened down fully and the four feet are all touching the ground. It could be a vibration from something not properly secured.

 

It's fastened alright. But the machine's hitting about 57 C right after Windows comes on. This can't be normal. The new fan I got is a Unicom ball bearing. Are they an OK brand?

The airflow setup in my case doesn't match any of the descriptions. I'll draw a pic in Paint and post it on my site and put up a link to it.