Recently loud (fan?) noise

[Hopkinfrog]

Hi!
My computer recently started making really loud noises now and then. This began about a week ago and it sounds like a fan problem. I bought the components and built the PC about 2 years ago. I've got a Asus A8N-E motherboard, an AMD 64 3000+ CPU and a zalman cpu cooler, can't remember the name... also worth mentioning is that I followed a guide on overclocking a year back, and did some tweaking in my bios. IMO the computer has always been loud but now it's like a failing car engine at times, and as I'm writing this the noise is almost constant for 2 minutes with a 2 minute break and then it starts again. It was my first time building the computer so maybe I did something wrong with the (in lack for a better word) cooling paste?

What I want to know is what I should do about this problem, I don't want my cpu to die on me, and I have a hard time actually localizing the problem when I open the computer. So maybe it's some other fan?

Thanks in advance
Hopkinfrog

 

[onestar]

Check for vibrations around your power supply. The fans supplied in some of them, are sleeved instead of ball bearinged and can cause quite a racket when they start to fail. An old trick from the automotive arena, is to use a long stick (18" or so) and hold it against the suspect part and your ear. (While the noise is occurring, of course) Such a direct transfer will usually pin-point the offending part.

 

[Onus]

While the noise is occuring, carefully manually stop each suspect fan. This may identify the noisemaker pretty quickly. What onestar said about PSU fans suggests checking that one first.

 

[jeremyrailton]

the only strange fan noises i've occurred was with an antec tricool that was wearing out and made strange noises at low rpm's, but was fine at high ones. also, make sure there aren't any cords hanging loose for the fan to hit. sounds like a simple fan replacement to me.

 

[evongugg]

If a fan is 2 years old and is critical such as the CPU heatsink and you are having noises, it is good to replace it.
Also check the speeds of the fans. They go slower when they wear out. Fans normally should not spin less than 2,500 rpms.
The other fans you can stop temporarily. Remove or stop the graphics card fan. Disconnect another fan until you find the cause.
The PSU fan is difficult to diagnose.