What are the symptoms of over-tightening spark plugs?

[MicahLee]

Symptoms of over-tightening spark plugs include gas leakage, so we must avoid excessive tightening when replacing spark plugs. Location of spark plugs: Spark plugs are installed on the side or top of the engine. Early spark plugs were connected to the distributor via ignition cables, but in the past decade, most car engines have adopted direct connection between ignition coils and spark plugs. Spark plug replacement procedure: Open the hood and remove the engine's plastic cover. Disconnect the high-voltage distributor wires, marking each cylinder's position to avoid confusion. Use a spark plug socket to remove the spark plugs in sequence. During removal, check for external debris like leaves or dust and ensure thorough cleaning. Insert new spark plugs into the holes, hand-tightening them for several turns before using the socket wrench. Reinstall the high-voltage distributor wires according to the firing order, then secure the cover plate.