Well damn. Now I feel bad if the valve cover difference is what is causing it! I recommended those to you thinking they would be the right ones. When I get a chance I can pull the coil cover off mine and verify the number on top of the coils matches what you have to make sure they did not send you the wrong part number. May not be able to get to it today though as I am pretty tied up with other stuff.

If it is valve cover height, I could buy them off you as future spares since I am the one that confirmed they work if Rock Auto wont take them back.

I do know just the person to ask about the valve covers though. I will message him now to see if he has one of each to compare. I can also try to find the threads where others did this change as well, to see if they had original AP1 valve covers or if they had already changed to an AP2 V1 cover

 

I have used 04-05 coils on a MY07 without any tangible issue. I'm sure they're somehow not right, but they do work.

I can't remember if I've used 04-05 coils on my MY01 with the original AP1 valve cover. I think others have, however. As mentioned before, maybe the Denso coils just kinda...worked if you mixed them onto a different generation.

NGK's design may no longer allow them to "just work" unless they are mated to the right gen of car/valve cover/whatever the difference is.

I have a couple MY06, MY04, and MY00-03 valve covers as well as a plethora of coils. What I'm lacking is the time to test out my theory.

I would recommend fitting a MY00-03 coil in each gen of bare valve cover to see if they protrude out more/less.

 

I shot a question over to the guy I know that likely knows the differences in covers better than most (Charlie M) to see if he had any input on it. I will post back when he responds.

I also tagged the OP in another thread about this to see if others chime in on what valve cover they are using.

 

I went to the NGK website and entered my 2009 info. It came up with 48664 U5245 but it also said it is NOT comparable with my vehicle. Why did it just not say no parts are available instead of giving me a non fitting part?

Guess I should think about getting some before they cannot be found. I have replacement wire sockets and inserts but not the packs themselves.

 

I don't blame you for buying those NGK '04-05 coils as that's what most of us would have done if we could not get Denso. In fact it's recommended to get the AP2/K20/K24 coil packs for the '04-05 generation of engines instead of the AP1 specific coils due to price. I'd be keen to try one of those NGK U5099 coils on my AP1 just to see if I have the same issue as you.

 

I seriously doubt that there's a tangible difference in VC height around the coil pack area over the years bruv. Then again it's worth a shot experimenting to confirm that.
In my case I've never had a fitment issue from switching to '04-05 coil packs from the original AP1's but they were all from the same manufacturer - Denso. OP might be the only user to experience a difference in design with the NGK's.

 

Is there anything stuck in the stem of the NGK coil?

 

Charlie Moua, who does the valve cover mods, powder coating, etc responded to me stating that there are no differences in AP1 and AP2 cover related to the coils and that the height is the same. So this is indeed strange. Now, I did not pull a plug on mine and see how it fit into the coilpack before I installed them, but the all sit down like they are supposed to when installed. If you give them a little push do they just feel like they are hitting a wall or just feel like they are getting tight before they go all the way in?

May be good to see if there is anything in the end of the coilpack as mentioned above. But that would be strange. Mine did not have anything in them (cardboard, etc) when I received them.

 

Can you stick a small screwdriver into the coils and compare depths that way? That will maybe determine if something in the contact/spring is in the way or if the fit around the plug diameter is the culprit.

Also, which plug part numbers are you running?

 

You read my mind. I was literally just psyching myself up to go pull out one of the original plugs (again!) to do this test.

New plugs in the car now: NGK 7746
Old plugs: NGK 7746

Both have the same fitment issue with the new coils.

Nothing in the coil aside from the spring, and they each have the same problem. I'll report back with a depth test.