Question Exhaust fan dying?

[Cal9099]

Something in my PC started intermittently making a very loud whirring sound and today I realised it's my exhaust fan.

Sometimes this will happen at boot up but then die down after a few minutes or sometimes occurs mid session and requires a restart to hopefully remedy. I also noticed today lifting and gently jolting down the case resets the whirring for a little while. I also noticed on CPUID HWMonitor that when this happens the fan RPM slows down from around 1000 to 500 RPM.

Is this a simple matter of the fan motor dying or is it a sign of anything more sinister with the motherboard, etc.?

Thanks!

 

[Lutfij]

Make, model and age of the fan? If the fan is a 3 or 4pin connector hooked to your motherboard, try and relocate to another fan header(while the system is powered down) and see if the issue persists.

a very loud whirring sound
You might want to share a video w/ audio of the fan producing the noise.

Just to be double sure, roll up a sheet of A4 paper into a cylinder, hold one end to your ear and then use the other end to probe for the source of the sound.

I also noticed today lifting and gently jolting down the case resets the whirring for a little while.
This is not a healthy practice to maintain for your computer.

Moved thread from Components section to Cooling section

 

[Lafong]

Very unlikely it is sinister.

You should be able to manually stop the fan at will for a few seconds to confirm your suspicions about the source of the noise.

You might try connecting the fan to some other connector on the motherboard just to see if that matters.

 

[Cal9099]

@Lutfij @Lafong thanks for your replies. The fan is a Corsair A1225M12S, 10 years old. I did manually stop the fan for a couple of seconds during one of its loud whirring phases and it stopped then started again upon releasing, so it's definitely that.

I'm not very techy so I'm not confident trying the fan in another connector. It doesn't look to me like there's another 3 pin slot on my motherboard to try it out on.

Is the issue most likely limited to the fan itself?

 

[Lutfij]

The fan is a Corsair A1225M12S, 10 years old.
Ah, we don't need that audio/video clip. Corsair made some of the worst fans in the industry and even their SP series of fans developed a rattle within a few months of use. Mind you, a decade ago they were trash. A decade later, I wouldn't invest in their fans.

 

[Cal9099]

@Lutfij Oh interesting, good to know. I assume the loud noise when the RPM falls is just the motor in the fan dying? Just curious to know what's going on as it's not a rattle in this case.

Best brand to replace this with?

 

[Lafong]

@Lutfij Oh interesting, good to know. I assume the loud noise when the RPM falls is just the motor in the fan dying? Just curious to know what's going on as it's not a rattle in this case.

Best brand to replace this with?

Could easily be bearings going bad gradually.

Are you particularly averse to fan noise...the whirring that they all do to some extent?

If you keep them from going above 1000 rpm, most decent fans will be virtually silent at 3 or 4 feet.

Your fan is likely 120 mm in diameter, so be sure to replace it with one of the same size.

Noctua fans are often recommended, but they are quite expensive...close to 30 dollars the last I looked. I haven't kept up lately, but I think I've heard good things about Arctic brand? You shouldn't have to spend over 10 or 15, maybe less.

I think that Corsair is an old fashioned 3 pin fan. They used to be common, but most fans nowadays are 4 pin. Your motherboard should accept either.

 

[BFG-9000]

0.38A is on the high side for a sleeve-bearing fan. Peel the sticker off the hub and pop up the rubber plug underneath to oil it. That should make it less annoying while you wait for a replacement to arrive in the mail.

 

[Paperdoc]

Do NOT oil the fan! With the more recent fans (even 10 years old) there is no way to get the oil to the actual bearings. You are much more likely to get it inside the case where it goes everywhere.

What you describe are the typical symptoms of a fan with its bearings almost worn out. The period of noisy operation on cold start-up will get longer until the fan completely stalls. You should replace it now. It is an older 3-pin fan (its female MOTOR connector has 3 holes), so I suggest you buy a 3-pin fan as replacement. A new-design 4-pin fan WILL work just as well, but those usually cost a little more.

You do not specify, but I believe this fan has NO lighting in its frame. Or IF it does, it has NO second cable for the lights - only the single cable that plugs into a mobo fan header. A new fan does NOT need any lights, and probably will use less much than the 0.38 A max current quoted in one reply above. Since it is used for case exhaust, it does NOT need to be a "pressure fan" - an "airflow fan" is what you need.

When buying, the SIZE quoted is the length of one SIDE of the square fan frame. Common fan size is 120 mm, but simply measure your old one.

 

[BFG-9000]

Do NOT oil the fan! With the more recent fans (even 10 years old) there is no way to get the oil to the actual bearings.

Corsair A1225M12S is a sleeve-bearing fan so is hardly a "modern" fan. It has a rubber seal under the sticker, under which you can actually see the axle in the sleeve bearing so just as with a ball-bearing fan should be oiled every 15-20,000hrs or so. No sealed fluid-dynamic or maglev bearings here!

That said, by the time there is a buzzing sound it's usually too late for oil to make the fan silent again because by then the bearing hole has been wallowed out and it's actually the axle shaft rattling around in there making the noise (as you'd expect, things expand with heat to take up some of the clearance when hot, so it tends to be loudest when cold). Surprisingly, if a sleeve-bearing instead squeals or even seizes to the point it will no longer turn freely, often oiling will get it to run silently again.

 

[Cal9099]

Thanks all for the input. I replaced the fan with a Noctua NF-P12 and everything's working perfectly.

 

[Paperdoc]

Thanks for the update.