On 2 Jun 2015 17:42:17 GMT, 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?

TIA

I'd check _every_ fastener on the entire unit; ensuring they are
tight. "Buzzing" makes me think of the motor as opposed to 'vibrating
of the metal covering the blower. Also check the tension on the belt.
Don't over tighten it. The belt needs a little wiggle so not to wear
the pulley bearing.