When replacing a spark plug, you need special tools to do the job easily. Spark plugs are usually screwed in deeply, which means that an ordinary hex cap will not give you enough grip. A spark plug cap offers the solution because these are usually longer and have rubber in the cap which keeps the spark plug firmly in place when installing or removing the spark plug. There are different sizes of spark plugs hence there are also different spark plug wrenches from 8 to 21 mm. Below you will also find various tools to test a spark plug and to repair the threads.

In short, here you will find all the tools to independently replace and test a spark plug.