Replacing the rod bearings on the S54 engine in the E46 M3 is a critical preventative maintenance step due to the engine’s known vulnerability to premature bearing wear. Over time, the rod bearings can degrade, leading to increased friction, oil starvation, and potential rod knock, which can cause catastrophic engine failure if left unchecked.

Since the S54 is particularly susceptible to these issues—especially in higher-mileage or track-driven cars—replacing the bearings before they fail helps maintain proper oil pressure, prevent severe damage to the internals, and ensure the engine remains reliable and performs optimally. Addressing this known weak point early can save you from costly repairs and prolong the life of the engine, making it an essential investment for any E46 M3 owner.