Which of the following symptoms could indicate a defective component in an air compressor?

High noise levels in an air compressor can indicate a defective component for several reasons. Abnormal sounds may arise from various issues, such as worn bearings, misaligned parts, or internal damage to the compressor. Noise that is louder than normal can suggest that moving parts are not functioning correctly or that there is an issue with the compressor's motor. Regular operational noise usually is within a range; when it exceeds that, it signals a potential mechanical failure that requires inspection and possibly maintenance or replacement of damaged components.

On the other hand, consistent airflow typically signifies that the compressor is operating effectively, so it wouldn’t suggest a defect. Low oil consumption is often a sign of a well-functioning compressor, particularly if it's designed to use oil for lubrication. Stable temperature readings indicate that the compressor is not overheating, which would be a positive sign rather than an indication of defectiveness.