When I started in the trade in 1999, there were still many oilable blower motors in service. As part of the maintenance, we would remove the housing and oil the motor. We would also vacuum the motor and wipe it down.

As oilable motors have become extinct, I see fewer and fewer techs pulling the blower housing. Here are some reasons you may want to consider doing it more often:

• Cleaning the motor itself can help it run cooler and last longer. A hot motor is not only more susceptible to winding breakdown but also to bearing/lubricant failure. Grab a vacuum, soft bristle brush, and a rag and get the dust buildup off the motor. If you have any dust that gets stuck inside, use some low-pressure nitrogen or compressed air to get it clean.
• Get in there and look carefully at the wheel. A wheel that is even slightly dirty can have a significant effect on air output. If it's dirty,  recommend cleaning.
• Check the blower bearings; it's easier to do when the motor is out.
• In high-efficiency furnaces, pulling the blower is a good way to check the secondary heat exchanger. On 80% furnaces, you can check parts of the primary exchanger and even the evaporator coil with a mirror or inspection scope.
• Pulling the blower gives you the ability to wipe down the inside of the furnace or fan coil.
• You can check blower mounting bolts, set screws, and blower alignment. You can also balance more easily.

Obviously, when and why you pull the housing will vary from contractor to contractor, but I advocate it being done more often than it is now.

What say you?

—Bryan