The answer to 'maintenance making noise' is that there are several common causes for HVAC systems making unusual noises, including worn parts, loose components, or issues with the blower motor or compressor. Symptoms may include grinding, squealing, or rattling sounds, and the solutions can range from simple DIY maintenance to professional repair.
Some common causes of HVAC noise include dirty air filters, worn bearings in the blower motor, loose or damaged fan blades, issues with the compressor, or problems with the ductwork. These issues can often be addressed through regular maintenance and cleaning, but in some cases, professional repair or replacement may be necessary.