For this you will need:
- 10mm socket+wrench or spanner
- 5/8″ deep spark plug socket + wrench
- Small flathead screwdriver or similar
- Six new spark plugs – NGK ILTR6E11 (eBay AU)
Which spark plugs to go for? Since you can get six of the Iridium plugs for under $100 on eBay and they generally seem good for 100,000km of driving it makes sense to us to use them – copper has a quoted life of ~20,000km and while you can probably get six for <$30 how much is your time worth to do this 5x over? Whichever way you go, onward to the procedure. The spark plugs are unsurprisingly located in your engine bay:

This is the engine bay of a 2012 Series II VE Commodore with the 3.6L LFX SIDI motor. The plastic cover on top simply unclips and can be then be lifted off:

The heat shielding/sound deadening piece at the back of the motor can now be removed – this makes accessing the rear plugs a lot easier and it’s only two clips:

Use a small flathead screwdriver or a trim removal tool to lift the center piece up:

Wiggle it forward and it can be removed:

It’s a coil-on-plug setup so you don’t have high tension leads going from a distributor to the spark plug cap – there’s one coil above each spark plug. The right side side (left as you face the engine bay – heat shielding/sound deadning cover left in place for this shot) – nearest to camera circled, three on this side:

Left bank (right side as you look into the engine bay) – the nearest to the camera is circled, you will see three in total on this side as well:

There’s a vacuum line running from the front of the airbox above the plugs towards the back of the motor here – it only takes a second to disconnect it at the front:



You can hook it out of the way easily. Make sure it doesn’t pull out at the back of the motor.

We like to do them one at a time. The coils unplug from the wiring harness easily:



A 10mm socket is required to undo the single bolt holding the coil-on-plug in place:



Removed (wiring loom plugged back in for the photo, no need for that… will get another photo):

Looking down into the spark plug well:

A 6″ extension with a deep spark plug socket ought to suffice:

Remove the old plug and grab some new plugs – we are using NGK ILTR6E11 plugs today (which can be found for a good price on eBay AU):



Install a new one and torque it to 7.2~14.5ft/lb. Note that these are a conical seat type and not the more common type with a crush washer. Repeat the process for the other three on this side and move on to the other side;

There’s a component in the way of the middle spark plug here – fortunately we can rotate it out of the way after we loosen and partially remove the bolt with a 10mm spanner or socket:



Don’t forget to replace it and tighten the bolt once you are done with that spark plug. Otherwise it’s the same again on this side as well. When you’re done don’t forget to put the vacuum hose back that you removed:

Clip the cover at the rear of the motor back in:



Put the top cover back:

…and you’re done!