Spark plugs ignite the fuel within the cylinder of internal combustion engines. The 2004 Saturn Ion has four spark plugs, one for each cylinder. Unlike other vehicles, however, the Ion uses a coil-on-plug setup instead of spark plug wires, where each spark plug has a separate ignition coil that amps up the battery voltage to the necessary power required to fire the spark plug. You can replace the spark plugs in your 2004 Saturn Ion with a few tools in about half an hour.
Park the Saturn Ion on a flat level surface and shut off the engine.
Wear a pair of safety glasses and disconnect the negative battery cable from the battery with a wrench. Move it aside so there is no chance it can contact the battery terminal while you work.
Locate the black plastic centerpiece with the words "Ecotec" on the center of the engine head. This is the ignition module.
Remove all six bolts around the outer edges of the ignition module using a ratchet.
Pull the ignition module directly up to remove it from the engine. The spark plug boots connect to the bottom of the ignition module and extend into the four spark plug recesses beneath the ignition module. Set the ignition module aside.
Insert a spark plug socket, connected to a six inch socket wrench extension and ratchet, into the left spark plug recess. Turn counterclockwise to unscrew the spark plug Remove and discard the old spark plug.
Adjust the gap of the new spark plugs to 1.0 mm using a spark plug gap tool.
Apply dielectric grease generously to the terminal end of the spark plug and insert it into the spark plug socket.
Insert the spark plug into the spark plug recess using the spark plug socket and turn clockwise. Ensure the spark plug turns smoothly at first; if not pull the spark plug out, realign and insert back into the engine.
Connect a torque wrench to the socket and extension assembly and tighten the spark plug to 15 foot pounds of torque.
Repeat on each of the other three spark plugs (four total). Reconnect the ignition module, following the removal procedure in reverse.
