G35 Spark plug replacement

OEM part # is 22401-5m015

TOOLS:

6 NGK LFR6AIX-11 Iridium IX Sparkplugs (these are 1 heat range cooler than stock)
3/8″ Rachet
3/8″ long extension (at least ten inches)
10mm socket
16mm “deep” socket (or “sparkplug socket”)
Magnetic pick up tool
3-prong grabber (optional, you’ll need it if you don’t have a “sparkplug socket”)
Pliers
Torque Wrench

Most people would have these tools in their garage. The long extension is a must. The magnetic and pronged “pickup tools” make this much easier.

PROCEDURE:

1) DISCONNECT THE NEGATIVE BATTERY TERMINAL!
2) Remove the engine cover. it is 2 10mm nuts and 2 10mm bolts
3) Remove the intake tube. This should require the removal of (1) 10mm bolt and 2 hose clamps. Don’t forget to disconnect the rubber breather tube; use pliers to loosen the clamp. Then pull the rubber tube away from the intake pipe.
4) Let’s start on the driver’s side first.
5) There are 3 coils on each head. They are held in place with a single 10mm bolt. Underneath these coils are the sparkplugs.
6) to gain better access to the coils, you’ll need to remove 3 10mm bolts which hold down an electrical harness just above the coils. All the bolts are easy to get to. You may have to push a couple hoses out of the way to get the back bolt though. Be careful not to drop the bolts!!! The magnetic pick-up tool can be very helpful here!
7) After you have removed the bolts for the electrical harness, Disconnect the plugs going to the individual coils. There are 3 plugs to undo. They are snug, but they come off fairly easily with just your fingers. Remember which plug goes to which coil. That is extremely important!!!!
8) Now you have good access to the coils! Use the 10mm socket to remove the bolt from the coil. Once you have removed the bolt, the coil will pull straight up out of the head. This should be very easy to pullout.
9) You should be able to see the spark plug in the hole. It is pretty far down there.
10) Use the 16mm socket with the extension to remove the plug. If you aren’t using a sparkplug socket, you’ll need to use a 3-prong, spring loaded pick-up tool. This tool makes plucking the plug out the head very easy. I’m sure you can come up with some other sort of tool to do the job, but that is what I used.
11) Replace the spark plug with your new plug! Torque the plug to 20 FT-LBs! Make sure not to crossthread or overtorque the plugs! Aluminum heads are easy to strip out!
12) Replace the coil; torque its bolt to 95 IN-LBs and plug it back in to the harness.
13) Repeat steps 8-11 for the other 2 cylinders!
14) Now, you have completed the driver’s side of the engine. Don’t forget to bolt the wiring harness back into position with its 3 10mm bolts.
15) You can also replace the intake tube at this time.
16) On to the passenger’s side of the engine.
17) This side is slightly harder….only because some of the bolts are difficult to reach by hand.
18) I started by removing 2 10mm bolts which retain the wiring harness. I only removed the 2 bolts closest to the front and middle of the head. The rear bolt is not necessary to remove.
19) You will need to remove the rubber breather tune that runs from the valve cover to the intake manifold. Use the pliers to loosen the clamps; then, slide the tube off of the engine.
20) Now, you should be able to disconnect the electrical plugs from the coils. This is the same as on the driver’s side.
21) The coil removal and plugs change is the same as described above. The only difference is that the back (toward firewall) coil bolt is difficult to get to with your fingers. Use the magnetic tool to remove and replace this bolt.
22) After repeating the procedure for all the cylinders, you should be done. Make sure to check that all the electrical connectors are snug and “clicked” tight.
23) Very important, you shouldn’t have any extra bolts laying around!!!!
24) put the engine cover back on. Secure it with its 4 fasteners
25) reconnect the negative battery terminal.
26) YOU ARE DONE!!!!!

Here is a video submitted by “ByThaBay”. Here is the link. It is a very detailed video, and will really be helpful if you’ve never replaced your plugs before.