Checking spark plugs requires comprehensive evaluation through visual inspection, resistance testing, spark testing, and gap measurement. During visual inspection, normal electrodes should appear light brown or grey; black carbon deposits may indicate an overly rich fuel mixture or incomplete combustion, while a white appearance could result from an overly lean mixture or overheating. For spark testing, connect the spark plug to the ignition coil and ground it-a stable blue spark indicates proper functioning, whereas weak or intermittent sparks require replacement. Gap measurement should be conducted with a feeler gauge; the standard gap typically ranges from 0.6 to 1.3 millimeters, and adjustments are needed if the gap is too wide or narrow. Regular spark plug inspections can prevent issues such as engine misfires and increased fuel consumption. Replacement is recommended every 20,000 kilometres or as specified in the maintenance manual. Using original equipment manufacturer (OEM) specified models guarantees compatibility. If insulator cracks or significant electrode wear are detected, immediate action should be taken regardless of the scheduled replacement interval.
