The answer to 'mini split making loud noise' is that a loud noise from a mini split air conditioner is typically caused by a mechanical issue that requires professional repair. Some common causes include a loose or worn fan motor, a compressor issue, refrigerant leaks, or problems with the outdoor unit. These issues can lead to loud rattling, grinding, or screeching noises that should not be ignored.
While some minor troubleshooting and maintenance can be done by homeowners, a loud noise from a mini split is generally a sign of a more serious problem that requires professional diagnosis and repair by a licensed HVAC technician. Attempting to fix the issue yourself without the proper training and equipment could make the problem worse or even create safety hazards. It's best to call in an expert to properly identify and resolve the root cause of the loud noise.