Spark Plug Heat Range
A spark plug’s heat range is the temperature range in which a plug works well thermally.
No matter what type of spark plug you choose, an optimal heat rating for your vehicle’s engine is important.
If a spark plug gets too hot, the excess heat it retains can cause premature ignition of the air/fuel mixture (known as engine-damaging knock) during the compression stroke before the ignition system actually fires the plug.
If a plug runs too cold, it can cause carbon buildup on the tip which leads to incomplete combustion and misfires.