Da z4-forum.com I was perusing the forum and found the link to change sparkplugs on the BMW's but when I went and did it I found that alot of the info is old or wrong for this style of engine. I had 48K miles on the plugs. Figured they needed a cleaning. Did it and took pics. Then I went driving.... Better low end throttle response and more midrange power. So here you go. First pic is of the Covers. One thing about BMW, nice clean install. Not cluttered with crap. Kinda hard to see the cover bolt covers. Better pic here. Just pri them off. Very easy, but unless you are careful, they will go flying.... You only have to take off the Right side cover. I took off both too see what was up. Very nice design. You only have to remove the two bolts for the covers. Everything else is plug and play... :worshipbmw: Here is a pic of all of the COP's (Coil on Plug). You notice the wiring and the two ground connections. These DO NOT need to be removed. Close up pic of the CO P. Now just lift up the connector hold down. This will unseat/remove the COP connector for you. No wiggling or stress on the wiring. Close up of the connector removed. Now just gently pull the COP out. You may have to wiggle (slightly) the assembly. In case you were wondering, I had already did Cylinder 1. Then I went and got my camera. The COP completely removed. Here is a closeup of the COP socket. Now you have access to the plug. If you have a large amount of oil in the plug well, get it out before you remove the sparkplug. All of mine were clean except cylinder 4. It had about three drops of oil in it, and I was not concerned about that. More than that, you risk the oil draining down into the cylinder when the spark plug is removed. Now remove the plugs. Here are mine before cleaning. Notice the nice brown/tan color. Seems to be burning well. No oil deposits indicating a potential problem. Now a cleaned plug. Installation is just the reverse. Very easy. The whole process (including taking the pictures) took only about an hour. Things to remember. I use a an air comressor and blow out the plug well before I remove the plugs. If you have oil in there, remove a much as you can. Use your hand to insert the plugs all the way down. If it take more torque than what your hand has, then there is a problem. Remove and and try again. Sometimes you may have to use a ratchet because there will be carbon on the tread surfaces in the head. If you use a ratchet, VERY little torque is required to get the plug to seat. I CANNOT STRESS THIS ENOUGH. If crossthread a plug, you risk a plug blowout. Some mechanics might be able to fix this problem in the car, the the only proper way is to remove the cylinder head and chase the threads with a tap or install a helicoil. Big dollars. (Been there, done that. :headbang: ) If you are slow and careful, it is really easy. The Service manual states that you DO NOT use grease on the plug threads. I take that to mean NO anti-seize. Use a torque wrench the reinstalling your spark plugs. According to the BMW Service Manual, the torque specs are as follows: Plugs with thread M12x1.25 is 17ft/lbs. Plugs with thread M14x1.25 is 22ft/lbs. As a Submarine Combat System Electrical/Computer Engineer, I work on a lot of OLD system. Remember, the wiring under the covers is subjected to long term high temperatures. Try not to play with the wiring unnecessarily. If you have a lot of miles, things can start to break. Don't be scared, just be gentle.
