How to Change the Spark Plugs in a 2002 Chrysler 300M

The 300M represents one of the ninth generation of Chryslers built between 1999 through 2004, based on cab-forward LH platform. Its 3.5-liter V-6 produces 253 horsepower. Changing the spark plugs on this vehicle was simplified when the distributor and spark plug wires were replaced with individual coils mounted directly over each plug. The coil-on-plug system delivers a more accurate timing and consistent voltage. The system also has the ability to recognize a misfire in individual cylinders.

Instructions

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.