Replacing your spark plugs is important and usually a fairly simple process, but if they seize in the cylinder heads it's an ...

Spark plugs are an essential part of a car's ignition system. As the name suggests, they provide a spark of electricity that ignites the fuel and air mixture, and gets the engine up and running.

Spark plugs that haven't been changed for a long time can become one with the cylinder head. Fortunately, it's possible to repair damaged threads instead of scrapping the head. (Photograph by Chris ...