GM 19300749 Spark Plug Asm

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The spark plug gap defines the distance between the electrodes and serves as the point where the electrical current can arc.

A typical spark plug comprises a metal shell encasing a ceramic insulator with a central metal electrode extending downward and a side electrode attached to the shell. The spark plug gap, measured in thousandths of an inch or hundredths of a millimeter, defines the distance between these electrodes, serving as the point where the electrical current can arc. The spark plug itself doesn't generate sparks but allows the current, ranging from 20,000 to 50,000 volts, to travel through wires to create sparks in the combustion chamber, igniting the air/fuel mixture. The spark plug's heat range, determined by the insulator's length, influences its ability to dissipate heat. Longer insulators operate hotter, while shorter ones run cooler. Selecting the correct heat range depends on driving habits, with long-distance, high-speed driving favoring colder plugs and stop-and-go driving favoring hotter ones. Replacement is typically needed every 20,000-30,000 miles, as wider plug gaps demand more voltage and affect engine efficiency. During removal and installation, care must be taken to avoid wire mix-up, and plugs should be tightened with proper torque specifications to prevent issues. Inspection, cleaning, and gap adjustment are essential maintenance steps to ensure efficient spark plug performance.

You can reference the Specifications section, the tune-up decal under the hood, or the owner's manual. Prioritize the information from the tune-up decal if there are any discrepancies.

Use compressed air or a bicycle pump to clean the area around the spark plug.