Chosen Solution
Some time, the fan on my Mac pro works very fast and it’s noisy also. Do I need to replace the fan?
Could be that you just have some dust built up on the heatsinks, which causes the computer to run hotter, which in turns causes the fans to kick up. Pop open the sides and see if it’s dusty. Anyway, no a loud fan does not mean you need to replace it, if you manually adjust the fans on an iMac it will sound like a jet.
I had a very noisy fan for a long time. Sometimes I could tap it and get it to quiet down. The “genius” bar folks said it was probably a foreign object that had been sucked into the fan. I finally replaced it and it is a joy to not hear it. From my experience, the answer to your question is “No, you don’t need to replace it.” On the other hand, if you do replace it, you may greatly enjoy the beautiful silence that will result. It is a VERY easy repair. –Kenoli
POSSIBLE SOLUTION: I have a MacPro 3,1 (Mfg Sept 2008) which I have used from 18 to 20 hours a day since it was new. A month ago it started having noisy intake fan issues (the dual fans at the front of the computer). At first I thought it was a harddrive issue, but after replacing all my harddrives with Intel Sata 3 SSDs (Speed Demon 520s, which make NO NOISE at all) I realized it was Fan Noise (sounded like they were out of balance during a cold boot). Well, to make a long story short, the problem appears to have been a nearly dead CR2032 battery. At least the problem has not reoccurred or recurred again since replacing the 3 1/2 year old lithiums. It is at least worth a try if your battery is several years old. Update Fan Noisy and sounds wobbly prior to the boot “Chime” (Bong) then it smoothes out. Discovered that my APC UPS backup power supply was defective and not generating smooth sine wave and/OR it was distorting the sine wave AC being fed to the computer.