Pontiac doesn't specify an oil change interval according to mileage for your 2006 G6 with the standard 2.4-liter engine. Instead the oil life monitor uses engine revolutions and engine temperature to determine oil life, though Pontiac recommends changing the oil at least once a year even if the oil change message hasn't appeared in the driver information center. Reset the oil life monitor in the DIC after you change the oil and filter in your G6.
Park your G6 on firm, level ground. Apply the parking brake and chock the rear wheels.
Remove the engine oil fill cap from the top of the engine. Grasp and pull up on the lower right corner of the intake manifold cover to disengage the retaining clips holding the cover to the air cleaner outlet duct. Grasp and pull up on the left side of the cover to disengage it from the studs, then remove it.
Position the floor jack between 6 and 7 inches from the front pinchweld flange and lift the front of the car one side at a time. Support it on jack stands.
Place the drain pan under the drain bolt and remove the drain bolt. Once the oil has drained, install the bolt and tighten it to 18 foot-pounds. Remove the drain pan from under the car and lower your G6 to the ground.
Find the oil filter cap in the front of the engine compartment, low and just to the driver's side of center. Remove the cap with the filter wrench or socket. The filter comes out with the cap. Remove the filter from the cap.
Install the new filter on the bottom of the oil filter cap and install the cap. Tighten the cap to -- but do not exceed -- 18 foot-pounds. Pour 4.5 quarts of oil into the engine.
Position the intake manifold cover over the studs and the air cleaner outlet duct. Press down on the cover above the left-side studs to engage the retainer clips, then press on the lower-right corner of the cover to engage the air cleaner outlet duct.
Install the engine oil fill cap. Start the engine and check for leaks. Turn off the engine and wait a few minutes for the oil to drain and then check the oil level, using the dipstick. Add the remaining 1/2 quart of oil as needed to bring the oil level to the "Full" mark.
