AC Compressor howling/grinding noise when turned on

Just started yesterday. Was fine all day, then heard a loud howling/grinding when the blower setting is turned on.

Could it be just a clutch bearing or is it the entire compressor?

 

There is only one way to know and that is to have someone turn it on while you inspect the compressor / clutch assembly when it is on. The clutch has no bearing of its own, it is assembled onto the compressor shaft.

If you see melted rubber around the clutch disk it may be just the clutch assembly that needs to be replaced.

If the clutch engages and the pulley spins, but the compressor shaft doesn't turn possibly the compressor is locked up.

Either way it will require someone being able to physically inspect the clutch and compressor in person.