wrote in message
oups.com...
I don't mind changing the motor myself, I already had the
thing out of the furnace. I could use a puller to get the wheel off,
but I am not sure about the furnace itself. 18 years old seems a lot
and I am not sure I want to band-aid it. I am new to the whole forced
air heating thing. Mostly lived with hot water radiators, but I am
learning. How do I know the heat exchanger is not cracked? How do I
know the furnace won't crap out a month after putting a new motor into
it?

My Opinion:

If you can replace the motor for $300 or less, do it.

At some point, have the unit serviced and the heat exchanger checked. I'm
running heaters in one building that are 29 years old and just put a new
belt on one of the blowers. Bearing were greased on both. I see no reason
that they will not last another 10 or more years.

On another boiler, it is 40 years old. I just had some valves and the
regulator replaced on the gas train as well as the motor on the burner.
Total cost about $1800, but new cost would be $35,000.