Of course, all air conditioners produce sounds, with larger and more powerful units louder than others. However, loud, mechanical noises emitting from your AC usually warrant further investigation, as this could be a sign that your HVAC system is overworking itself.
When your AC has been in use for years, its internal components have been subjected to wear and tear. Such wear and tear can lead your AC to malfunction. As a result, your AC overworks itself while continuing to operate in this state. In this instance, contact your servicing company immediately, as prolonged use can lead to significant damages and costly repairs.