If it's a creaking noise then it is most likely that your compressor is broken.
Your central air conditioner may make a loud noise when it comes on. This is because it may have a leak somewhere in the system.
Loud noise is not a good description. If its a loud squeal turn the air conditioner or defroster off. If the squeals goes away the compressor or the clutch for the air conditioner compressor is locked up.
1. A bad or worn out drive belt. 2. A bad or damaged a/c clutch. 3. A bad or locked up a/c compressor.
hydraulic lifters.
Your A/C belt is loose and needs to be tightend or replaced.
Lack of oil lubrication to the valve lifters.
The bearings are out of it. Replace Blower motor.
Because while your air conditioner is activated the air from outside is coming in being purified and is then released so its like a vacuum of some sort!
Loud and sustained or repetitive noise.
repace the fan belt that drives the a/c unit. If it doesn't fix it, it's the a/c pump. Very costly. Live with the noise.
Maybe a bad bearing in fan motor
Probably not. Depends on the decibel level and how long you're listening to it. If it's loud enough to damage your hearing, you desperately need to get an HVAC person over to fix it.