The M54 engine features a 1-piece crankshaft harmonic balancer integrated with the hub. Begin by raising the front of the vehicle and supporting it safely. From below, remove the front splash guard and the electric cooling fan along with the cowl, taking care to protect the radiator from damage using a piece of thin plywood. With the engine fully cooled, mark the direction of rotation on the engine accessory belts and remove them. Bolt BMW special tools 118190 and 118200 together, inserting the fingers of tool 118200 into the harmonic balancer openings to counter hold the harmonic balancer hub while loosening the mounting bolt. Ensure an assistant holds the special tool; if unavailable, rest the handle on the front subframe, protecting it with wood. Avoid using the flywheel locking tool to hold the crankshaft stationary during this process. Remove and discard the harmonic balancer mounting bolt, then pull off the harmonic balancer using tools 118210 and 118200. Inspect the front crankshaft seal for leaks, replacing it if necessary. When reinstalling, align the harmonic balancer groove with the crankshaft woodruff key and insert a new mounting bolt and washer. Inspect the woodruff key for damage before installing the harmonic balancer, replacing it if needed. Use tools 1118190 and 118200 to counterhold the harmonic balancer while tightening the mounting bolt, and refrain from using the flywheel locking tool for this task, opting instead for the recommended special tools or equivalent.