How to Replace Spark Plugs on a 2002 BMW

1. Open the hood. Remove the cover for the cabin filter and housing located near the windshield. Twist the plastic knobs that hold it on and lift off the cover off.
2. Remove the cabin filter and disconnect the wiring harness that goes to it. Remove the filter housing by unscrewing the four Torx screws that hold it in place. Pull the enclosure out and set it aside.
3. Remove the top engine cover. First remove the plastic covers that conceal the engine cover bolts. Remove the bolts with a 10mm socket and lift off the engine cover. Remove the oil cap and remove the remaining engine cover in the same manner as the first.
4. Remove the wire coils for the spark plugs, noting which plug each coil goes to by marking it with a piece of tape and a marker. You can also simply change one plug at a time so as not to mix up the coils. On some models, the coils are bolted on and on some the coil is simply rotated and pulled out and off of the plug.
5. Insert the spark plug socket (mounted on the 6-inch extension) into the hole that the spark plug is located in until you feel it seat on the plug. The spark plug socket has a rubber insert that grabs the plug.
6. Loosen the plug by turning the socket counter-clockwise with the ratchet. Carefully pull the plug out of the hole so as not to drop it.
7. Gap the new plug according to the plug manufacturer's recommendations, bending the outer posts with a plug gapping tool until the proper gaps are achieved. Apply some anti-seize compound to the plug. Slide the plug into the spark plug socket and then tighten the plug into the engine. Use a torque wrench to tighten the plug to 30 ft. lbs.
8. Press the coil back onto the plug and fasten it with the bolt or install it in the reverse of removal. Repeat the above steps for all of the spark plugs in the engine. Replace the engine covers, the cabin filter housing, cabin filter and housing cover.