Spark Plug Overheating

SPARK PLUG OVERHEATING

Spark Plug Overheating:

Overheating is indicated by a white or gray center electrode insulator that also appears blistered. The increase in electrode gap will be considerably in excess of 0.001 in. per 1000 miles of operation. This suggests that a plug with a cooler heat range rating should be used. Over advanced ignition timing, detonation and cooling system malfunctions also can cause spark plug overheating. Also check for lean air-fuel mixture. Check the torque value of the plugs to ensure good plug-engine seat contact.