Replacing spark plugs is a basic necessity for just about any vehicle on the road. On the BMW E36 six-cylinder engines, BMW has eliminated the use of spark plug wires by using six small coils that sit on top of each spark plug. It is a bit more expensive but it makes the car’s ignition system more reliable by removing a component that constantly wears out and fails. Most models still use everyday spark plugs.
It’s best to replace spark plugs once a year or about every 16,000 kilometers, whichever comes first. You can usually get away with going longer, however, you never really quite know how long the plugs are going to last, or you may forget to do it if you don’t setup a yearly schedule. Replacing your spark plugs is one of the easiest tasks to do on your BMW.
To start, make sure the car is cold. Removing spark plugs from a hot car can be harder and cause possible damage to threads in the cylinder head. Next remove the top plastic engine covers. There are two covers on the six cylinder vehicles – a long thin one on the top of the car, and a wider one towards the left. There will be two small, snap-in plugs on the top. Carefully remove these plugs with a small screwdriver. Underneath you will find a nut that holds the cover onto the top of the engine. Remove the four nuts on these two covers and you can get them out of the way.
There are coils on each of the plugs under the cover. Release each connector using a screwdriver. Do this by lifting up on the retaining ring that fastens the coil. Gently place the wires off to the side and out of the way, without bending them terribly. With the wires detached and out of the way, you can now remove each of the six coils. On two of the coils, there are two small ground straps that connect the coil to the stud on the cylinder head. Remove each of the two nuts that hold each coil to the valve cover. Simply remove the coil/plug assembly and place it off to the side.
Turn the spark plug counterclockwise using a breaker bar. Once it is loose use a spark plug wrench to pull it out. Install your new plugs using a torque wrench to measure the amount of torque applied to the plug. This is very important because it is easy to over or under-tighten spark plugs. Make sure that the plug is firmly in place in your spark plug socket. With the new plugs installed and properly torqued, you can replace the coils and reattach the coil connectors. Snap the wires back into their center holders and replace the top two plastic covers. When you’re done, your engine should look back to normal.