Nissan Maxima engine knocking noise at idle, possibly related to main bearing issue on Nissan Maxima

Some Nissan Maxima owners report experiencing engine knocking noise at idle, often linked to main bearing issues. This common problem is frequently associated with insufficient oil levels, which can lead to inadequate lubrication and subsequent knocking sounds. Specifically, owners of 2009-2014 Maxima models have noted that the #1 main bearing can be a particular source of concern. Diagnosis of the knocking noise can be confirmed by recognizing symptoms such as the noise being audible at warm idle but not during cold starts. Additionally, a service bulletin (NTB 12-071) exists to address factory bearing problems, recommending the use of a stethoscope for accurate diagnosis. It is crucial for owners to promptly diagnose and resolve this issue by checking ignition timing and using the recommended fuel grade, as neglecting these concerns may lead to more severe engine damage. The knocking noise can be quite loud, especially after highway driving, making it important for owners to take action to maintain their vehicle's performance.