The answer to 'tune-up making noise' is that there are several common causes for a noisy HVAC tune-up, including worn or loose parts, debris buildup, or issues with the blower motor. Symptoms may include grinding, squealing, or rattling noises coming from the unit.
In many cases, these issues can be resolved through a professional tune-up and maintenance service. However, if the noise persists or worsens, it may indicate a more serious problem that requires the attention of a licensed HVAC technician. Attempting to troubleshoot or repair the issue yourself could be unsafe and may void your equipment warranty.