When to replace a fan

[melvin]

Both a general and specific question... I repaired an SVT-4 Pro last week (thanks for the help) and something occurred to me about the whiny fan. Knowing it's quite crucial to the operation of this thing and hearing it whine when warming up, I wonder what kind of maintenance or checks I should do on a fan before sending something like this home. Usually I just make sure it works (I don't see a lot of them), but now I wonder if it could have been part of the problem.

[Steve Conner]

I'd always vacuum out the dust from the fan and surroundings if I had something like that open. Sometimes the fan has sticky dust caked onto the blades, and taking it off makes it run quieter.

If the fan makes nasty squealing, grinding noises and won't come up to speed smoothly (hard to describe, the only thing I know that sounds like it is a car with a shot water pump bearing) then the bearing's days are numbered and the fan needs replaced.

[Gtr_tech]

What he said. And I'd replace it with a good quality ball bearing fan. Those sleeve bushing jobs only work well for a while. When they start squealing/chattering the sleeve "bearings" have exceeded their life expectancy.