BMW Spark Plugs

Remove ignition coil covers and unlock the ignition coil connector, then pull the connector off the coil and slide the rod-shaped ignition coil straight out of the spark plug hole. Maintain cleanliness when servicing ignition coils, as fuel and oil residue can lead to a breakdown in the electrical resistance of the silicone-encased coil, resulting in failure. For spark plug removal, use a special 12-point spark plug socket for turbo engines and a thin-walled spark plug socket for non-turbo engines. If a thin-walled socket is unavailable for non-turbo engines, carefully remove slotted ignition coil sleeves from the cylinder head cover holes before taking out the spark plugs. Inspect the spark plug electrodes, with light grey indicating normal combustion. For installation, follow the reverse order of removal while lightly lubricating new spark plug threads with copper-based anti-seize compound, threading plugs into the cylinder head by hand to avoid cross-threading, reinserting or replacing slotted ignition coil sleeves if removed, and carefully inserting ignition coils into the spark plug wells before reattaching electrical connectors.

6-cylinder engines in E90 vehicles (N51, N52, N54) utilize a coil-over-spark plug configuration, featuring one ignition coil positioned above each spark plug. To remove the spark plugs from the turbocharged (N54, N55) engine, a special thin-walled 12-point spark plug socket, BMW part no. 83 30 0 495 560, is necessary.