• Cold engine
• Spark Plugs x4 (NGK FR5CP, Stock no 6368)
• 8 mm socket for plastic cover
• 10mm socket for coils
• 16mm deep socket to remove spark plugs
• Wrench, long extension (250mm in my case and had space to spare)
• Torque wrench which has adjustments for 18-22Nm
Remove the cover by loosening the 4 x 8mm hex screws. The black plastic cover on its right side just unplugs with the red part of the cover once the screws are undone (screws stay with the cover)
You should now be looking at the coils.
Remove the battery negative terminal and remove the connector attached to the coils.
Loosen the 10mm hex screws, take the adjacent wiring harness out of the way and gently pull each side until all connectors pop off the spark plugs. Once free, put the coil plugs aside. You should now be looking at the spark plug access holes.
Use the specially designed 16mm socket, in my case it uses a rubbery insert to attach and securely hold on to the plugs in order to pull them out, and loosen and remove one spark plug at a time.
Replace each removed plug by gently inserting by hand using the extension and screw it into place until it can no longer be turned by hand. At this point I use a torque wrench first set at 10Nm and then at 19Nm (my manual suggests a toque setting between 18Nm and 22Nm).
Place everything back using the reverse order, noting that both the 10mm and 8mm screws just need a slight turn (say ¼ turn) past the can-not-turn-it-more-by-hand point.