Oh just forgot something.
if the bearings reach there end ,you engine gets more noisy.
And also there is a second wistle sound when you start ,and shutdown the engine.


you also can feel it when you spin the rotor with your fingers, and on your data terminal you can see the time of running down getting shorter.
very important when you run the engine for the first time to wright down the time of running down the rotor of the engine.

Regards,

Martin.