Once the pinnacle trim level of Chevrolet’s legendary Chevelle, the Malibu is now a front-driven family car. The 2006 Malibu had three engines available: The base level was a 144-horsepower, 2.2-liter engine, the optional V-6 engine was a 3.5-liter and the top level engine, which came only on the SS trim level, was a 240-horsepower, 3.9-liter V-6. The only engine that has obstructed rear spark plugs is the 3.9-liter-equipped SS model, as there is a large plastic cover on the engine that impedes your access to the rear plugs. Once you remove this cover, swapping out the rear plugs is simple.
Check the gap on all six new AC Delco 41-100 or equivalent spark plugs using a spark plug gap tool. The correct gap for the 3.9-liter V-6 engine is 0.038 to 0.042 inches. Exchange any incorrectly gapped plugs for new ones, as these plugs are not adjustable.
Unscrew the oil filler cap from the top of the engine. Grip the plastic cover on top of the engine and pull upward firmly to disengage it from the retaining studs. Tighten the oil filler cap onto the engine.
Trace the three spark plug wires toward the rear of the engine until you find the thick rubber boot on the end of each wire. Grip the boot on the far passenger’s side and twist it a half turn, then pull it upward to disengage it from the spark plug.
Remove the exposed spark plug with a ratchet and spark plug socket. Pull the old plug from the spark plug socket.
Thread a new spark plug into the vacant hole in the engine by hand. If you feel any resistance while tightening the plug, immediately remove it and thread it again. Tighten the spark plug to 15 foot-pounds with a torque wrench and spark plug socket.
Inspect the disconnected spark plug wire for any defects, including breaks, splits, burns or brittleness. If any defects exist, replace all six wires one by one as you remove them from their spark plugs. Always keep track of how each wire routes around the engine and route the replacement wire exactly as the old wire was routed.
Apply a dab of dielectric grease to the inside of the spark plus wire boot and spread the grease around with a small flat-head screwdriver. Press the spark plug wire boot onto the spark plug until you feel it click into place.
Repeat steps 3 through 7 to replace the remaining two spark plugs and wires, if needed, on the rear of the engine.
Trace the three spark plug wires toward the front of the engine until you reach the thick rubber boot on the end of each wire. Twist the boot a half turn, then pull it from the spark plug.
Follow steps 3 through 7 to replace the exposed spark plug.
Repeat steps 9 and 10 to replace the remaining two spark plugs on the front of the engine.
Remove the oil filler cap. Set the engine cover back on top of the engine, aligning the cover’s retaining grommets with the retaining studs on the engine. Press downward on the cover to lock it into place. Tighten the oil filler cap.
