The fan cools the motor to prevent it from overheating. Replace the fan if any fins are missing or if the hub of the fan is cracked. There are various types of fans from “squirrel cage”-type to propeller-type. Running the unit without a fan will cause it to overheat and possibly damage the motor.
This item fits the following models:
15-pc Thunderbolt Black Oxide Drill Bit Set
1/4" x 50 Ft Noodle Air Hose with Coupler and Plug