"Stormin Mormon" wrote in message
...
From your descrip, it sounds like it might be a booster fan to move the
flue
gasses up the pipe. Sometimes those have an oil hole on each end of the
motor. Couple drops of SAE 20 or SAE 30 oil might quiet things down.

Some years ago, I had a blower fan in my trailer furnace start to squack.
Really enough to drive me out of the house. I took the blower cage out,
and
found that it had oil holes. Put in a couple drops of oil, and it never
bothered me again.

You've said in the past that you have to do the oiling every couple of
years.

Get your story straight.....