Friday, April 10, 2020

DIY Spark Plug Change

I have a shop manual and have viewed a couple videos but they leave out some steps that might be helpful to others:

1. Remove engine cover - the front lifts then the back edge pulls forward. It's easy for one of the two rubber receptacles for the back tabs to come out and end up on top of the engine. I put a bit of duct tape around the outside of the rubber piece so it would stay in place.

2. Remove the air cleaner box cover and the main air duct, and it's related electrical connector, and two hose connections, and one 10mm hex head bolt. Place a rag in the lower air duct that you didn't remove to prevent anything falling in. And put rags over the air filter element to keep it clean. Remove the rear-most intake duct (between the air cleaner cover and the main air duct) by popping it up off it's plastic stud and move it aside without damaging the electrical cable that goes to it.

3. You can now access the front 3 coils and spark plugs. To access the 4th you need to remove a torx head screw and a pair of wire connectors and their bracket to push them aside.

4. To access the 5th and 6th coil and plug you need to remove the plastic cable track that runs crosswise just ahead of the firewall. There's 2 torx screws on each end. On the passenger side you'll actually see 3 torx screws but the middle one does not need to be removed. There was a thick rubber pad that had to be flipped out of place to expose the 2 passenger side torx screws.There was the 12 volt battery cable and a smaller electrical cable in my cable track that need to be lifted out and pushed aside before the cable track came free.

5. To remove a coil connector just lift up the end of the coil connector cover and it will push the connector free. Then grab that cover and pull straight up and the coil comes off the plug.

6. To remove a plug use a quality spark plug socket specific to BMW. Don't skimp on a cheap tool, this is not a place where you want to take a chance on a failure. You'll need a bit of flex in your extension, I used a 3/8 drive Harbor Freight Wobble Extension. About 12 inches long for the front 4 plugs but only 6 inch for the rear two. You can use the 6 inch long one for all 6 if you want to. The spark plug socket will capture the plug as you remove it. I used a small vacuum on a piece of half inch hose to vacuum out any debris so it didn't fall in the cylinder.

7. To replace the plug put the new plug in the socket and use the wobble extension to get it started and snug using finger thight only, no ratchet so you don't cross thread it. Torque it with a wrench to spec. But here's the catch. After you've torqued it, when you pull out the extension, the socket will likely stay on the spark plug. I used a long needlenose plier to reach down and grab the socket and pull it off the plug. If you don't have a tool that will reach down and grab the socket don't attempt this job, you'll never get the socket off the plug and you'll be stuck.

8. It might appear daunting to do the back 2 plugs because of the awkwardness and limited access but it's easier than it appears. Just start at the front to gain experience before trying the back 2.

9. Reinstall the cable track, cables, and all the other parts you removed and you are good to go.