My 2006 550 is in need of a spark plug change and i refuse to spend money on a job i know i can do myself...My question is before i start are there any diagrams showing exactly what i should be taking apart to get to the plugs*i took the main plastic cover off just to get a look at what i was diving in too but decided to ask 1st on here to get a couple pointers on what i should and shouldn't touch seeing that this is my 1st BMW and i dont want to F things up*.....If anyone can shoot me a couple words of wisdom i would appreciate it

 

I heard its hard to get to the last plug in the back and you need a special tool, but im sure someone else can chime in.

 

I recently did the plugs on my 545i and the toughest part is plugs #4 and #8 which are the rear plugs against the firewall. I have not worked on a 550i, so I can't speak to whether the layout of all major components is the same as the 545i, but I can't imagine there is a large difference. You may want to search for additional DIY procedures on this and other forums that may be specific to the 550i.

Three of the tricks I picked up from the DIYs online:
1. Use a piece of rubber tubing to insert the new plug and get it started (insert the plug into the tube and then feed it into the hole and carefully spin the tube in your fingers - you can feel the thread catch and turn it in until snug before putting the spark plug socket and torque wrench on it).
2. The method of attaching socket fittings together, including universal joints and then using electrical tape to insure they don't come apart
3. Which additional engine components must be removed or loosened and moved out of the way.

Yeah it is time consuming, but not brain surgery. I was also able to snag Bosch plugs on sale with a rebate for $3 each ($24 total incl shipping), so the savings was especially sweet over paying a $tealer or Indy to do what I can do myself. I argued with myself about replacing the ignition coils while I had them out, but I decided not to as they seemed fine.

If I had it to do over again I think I would replace the ignition coils in #4 and #8 ports as if required the other six could be done in 30 minutes. But #4 and #8 take quite a bit longer given what needs to be moved to get those two ignition coils out.

If it is the first time you have done plugs I suggest you do one plug at a time from start to finish. For the first two or three plugs you may want to start the car and run it for 10 seconds to make sure all sounds well (don't let it run more than 10 seconds as it will warm up fast and you will have to take a break while it cools down.

 

I replaced my plugs about a month ago on my 2006 550i, like others said, #4 and #8 are tricky, but not impossible.