How to Change the Spark Plugs in a 2002 Chrysler 300M
- 1). Disconnect the battery negative terminal, using a wrench. Unplug the electrical connector on each coil just prior to removal of the coil. Remove the two 10-mm bolts securing the coil to the valve cover, using a socket.
- 2). Rotate the coil 90 degrees to break it loose from the plug, and pull it straight out of the valve cover. Remove the spark plug by turning it counterclockwise, using the spark plug socket attached to a 6-inch extension.
- 3). Gap the new plugs to 35 thousandths of an inch, using the gapping tool. Install the new plug by turning it clockwise until it stops, followed by an additional 30 degrees to compress the spark plug ring.
- 4). Install the coil by pushing its boot down on the spark plug and installing the bolts and tightening them firmly. Plug the electrical connector into the coil. Repeat the process for the remaining plugs. Install the battery negative terminal, when finished, and tighten it firmly.
Source...