On 06/02/2015 12:42 PM, KenK wrote:
My swamp (evaporative) cooler makes noises after it
has been run a week or so every year. A buzzing
noise. I can quiet it by pressing firmly on the front
inside grill/panel towards the bottom. I tried adding
soft washers under the four corner screws fastening
this grill last year but it didn't help. I'm not sure
whether the grill is causing the noise because it has
a mounting problem or, more likely, the blower is
vibrating and causing it to buzz. Just yesterday I
tried lubing the blower bearings again (after
prepping it for the summer a month or two ago) but no
help. I can't see anything obvious causing the
problem. The belt looks ok. This cooler is only a few
years old - third season I think, maybe fourth.

Can anyone give me any ideas on how to chase this
down?

That if can be stopped by force against a mechanical piece indicates it
is vibration...as you say, likely it's transmitted from the motor/fan to
the case. The PC case here is bad about that for the side cover...

I see you got out the tools in another thread but it wasn't doing
anything at the time; wait until it starts up again and then begin
adding a damping pressure at the various points of likely candidates--it
could even be the actual sheet bottom at a resonance or some such.
It'll be seek and destroy to find the actual culprit; the stethoscope to
listen/localize is a good technique for the purpose.

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