The operating temperature of a spark plug varies between 450-870°C. At 450°C the spark plug reaches its self cleaning temperature; this means that carbon deposits which are produced during combustion are actively burnt off the insulator nose. When too many carbon deposits accumulate along the insulator nose carbon fouling occurs and engine misfire may occur. If the temperature of a spark plug exceeds 870°C overheating may occur leading to spark plug and possible engine damage.