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.

Let's say you've just removed an old spark plug. Does it have any life left in it? Can it be reused if it is cleaned properly? Let's take a closer look.

Spark plugs are typically the firestarters of an internal combustion gas engine. And when a spark plug goes wrong, it could potentially mean a host of problems like engine knocking, misfires ...