Remove the engine cover and then remove the coil packs. The coil packs are connected on a single wiring rail so you need to undo all four plugs at the same time.

Coil packs just pull out but they are stiff to get out.

Coil packs just pull out but they are stiff to get out.

Gentle leverage may be required, a large flathead screwdriver may help.

So can some one tell me if this 'Iridium' spark plug has any real benefit over the OEM or is it just a load of waffle?.

I've had them in two mk4 astras a 1.8 and the 2.0T. The 1.8 felt a lil more crisp as so to speak.

The 2.0T had a issue with the standard plugs that at idle the revs would drop for a split second and make it shudder slightly.

Went through 2 sets of vauxhall jobbies and never sorted it, put iridiums in and it cured it.

i think i might wait to a meet and get someone to show me as ive heard many stories on how hard it is to change them on octy's.

i think i might wait to a meet and get someone to show me as ive heard many stories on how hard it is to change them on octy's.

You must be listening to the wrong people Paul, it is well within your capabilities mate.

do i need any specialised tools as i remember the last time i changed them was on my astra and they had decided to put them right down inside where as previous cars you could easily undo them by tingers once you had removed the tension.

They are quite low down in the head so you'll need a plug socket and a long extension bar, nothing that isn't in your average socket set.

Be careful levering the coil packs, I read a bulletin recently which cited that as a common cause of failure.

ill wait till after the service in a couple of months and add a grade cooler then probably be looser then too!!