Silavent SDF150 First Activation After Years Rusty Exhaust Fan

this is a rare 6 inch extractor fan in a bathroom this fan has 5 blades and has no shutters on the outside

[@Wildlifesupernannyfan]

Sounds like it has a radial engine!!

[@HoardersUnion]

It's most likely the metal bearings gone rusty from condensation and not used for a while,
The bearings are used for the axel to spin on to prevent vibration in the engine and blades.