Before starting your furnace for the season, it is a good idea to clean and lubricate inside the furnace. One way to help your furnace last for years is to lubricate the blower. There are two lubrication points on most draft inducer blowers, although there are sealed motors that do not require lubrication. If you have a serviceable blower motor, it has one or two oil ports. Lubricating a furnace draft inducer blower also includes the motor shaft where it enters the bearing collar of the blower wheel.
Turn off the circuit breaker to your furnace. Go to the furnace and remove the service panel from the blower compartment. Depending on your furnace, the service panel simply lifts up and off the furnace, or it might have screws securing it to the furnace, requiring a Phillips screwdriver for removal.
Put on safety goggles or glasses. Spray compressed air where the motor meets the blower wheel housing. This removes dust and dirt away from the blower motor shaft. Wipe the top of the motor with a clean rag to remove dust and dirt from around the oil ports.
Find the two rubber caps that cover the oil ports on the motor. The caps might be on the side near the shaft or on the top of the motor body. Pull the oil caps off the motor with your fingers. If there are no oil caps, chances are the motor is sealed and requires no lubrication.
Apply two to three drops of 3-in-1 oil to each port. Push the caps over the oil ports.
Spray a thin film of silicone lubricant on the motor shaft where it enters the blower wheel bearings. Reinstall the service panel, then turn on the circuit breaker to power the furnace.