[SOLVED] Whining CPU pump

[Kanepoo69]

So I made a thread before about a loud whining AIO pump. since getting a replacement it's doing the same thing. the RPM drops from 2000 to about 400 and makes a really loud whine and grinding sound. I've tilted and shook it incase of air and no luck. some days it does it and a restart will fix it for a couple weeks but then it'll do it again for a bit. any ideas?

 

[CompuTronix]

Kanepoo69,

The "whining" and RPM change you've described is a symptom that's commonly associated with "bearing chatter". A worn CPU fan or case fan will make similar sounds. It's the telltale sign of bearing failure.

Bearing chatter occurs when excessively worn bearings that support each end of a motor shaft, have developed too much clearance between the working surfaces. The clearance is greatest when the shaft and bearings are cold, such as during first power-up.

As the motor begins to rotate, the shaft will rapidly oscillate or "chatter", which restricts the motor from rotating freely, thereby limiting the RPM. But as the friction causes the surfaces to warm up and expand, the clearance decreases, the "chatter" stops and the RPM spins up to normal ... for a while. However, it's fairly typical for bearing chatter to become random, just as you've described.

If the replacement is from an RMA, did they return the same serial number to you ... perhaps because they couldn't duplicate the problem?

If the replacement is new, it may be from a faulty production batch due to a design or manufacturing flaw, as could be the case with your original unit.

Regardless, there's nothing you can do to fix a faulty pump motor with bearing chatter. The only solution is to RMA or replace the unit. You may want to choose a different brand and / or model this time.

CT