Disconnect the fan, Now. Most have a thermal overload but a Chinees job might not.
The Water-Displacement Formula 40? Not in itself, no.
But, it can drive outside dirt into the bushings, or drive out what lube is left. Bushings are often permanently-lubed sintered-bronze, better no lube than dirt forced in.
It cannot damage windings. They are heavy formvar, good for 400 degrees. Only very old shellacked windings from something from 19th century would be damaged. Unless they had been overheated, anyway, and were ready to go.
Do as others suggest, take it apart , lube bushings, see if armature rubbing.
Repaired many fans, small motors, vacuum cleaners. I lived in San Diego once, WD-40 was invented there to get moisture out of boat distributors. Never designed as a lube.
· 1 month ago