Where is the car spark plug located?

[VonRuby]

Car spark plugs are installed on the side or top of the engine. In early models, spark plugs were connected to the distributor via ignition cables, but over the past decade, most passenger car engines have been modified to have the ignition coil directly connected to the spark plug. Spark plug working principle: The spark plug's ground electrode is connected to the metal shell, which is threaded into the engine block through the cylinder head. The insulator primarily serves to isolate the metal shell from the center electrode. The terminal nut is the part of the spark plug that contacts the high-voltage coil. When current passes through the terminal nut and the center electrode, it ionizes the medium between the center electrode and the ground electrode, generating a spark to ignite the air-fuel mixture in the cylinder. If a spark plug is damaged, it can directly cause issues such as ignition system leakage, increased fuel consumption, reduced power output, and most notably, difficulty in starting, affecting the vehicle's normal operation. Severe spark plug erosion—evidenced by pitting, damage, or melted electrodes at the spark plug tip—indicates that the spark plug is damaged and should be replaced.