[surfariver]

Jsut rolled through my first spark plug change for my 06 325xi and things seemed easy, a little too easy...

When I started it, it was running pretty rough and appeared to be missing. After playing around for a while, it appears that the #4 boot was not sitting all the way on the spark plug. After pulling all of the boots back off, it actually appears that the #4 boot is different than the other 5!

Its gray while the others are black/brown and when, outside of the engine I stick a sparkplug into it, it doesn't grab the plug and I can wiggle it around quite a bit (when I do this with one of the other 5, it kind of "clicks" into what I think is a female metal part inside of the coil and there is no 'wiggle' when its in).

Impulsively, I took this odd coil and started cutting away the rubber protection from the bottom up. Inside, there is a male metal contact with a small spring in the middle. Its almost as if the plug end is supposed to touch end to end to the male part but the spring (not very strong one) is pushing them apart.

I'm at a loss, car has $100k miles and I've always had it serviced under the service plan at the dealership. Of couse, a new coil is not in stock at Auto Zone or Advanced Auto.

Does anyone have any thoughts on this? Am I stupidly missing something?

Thanks!

[surfariver]

Looking through my records I see that the dealership did replace the #4 coil back in 2009 but as far as I can tell, the other 5 coils are original.

My car was manu'ed 09/2005 so it appears it should use coil 121 375 949 36. The images I've seen online show a gray coil, just like the one I pulled off.

However, I also see images of the 121 375 949 37 which are supposed to be for my model year manu'ed after 04/2006. These coils look like the other 5 (the ones that seem to snap the sparkplug in).

The more I figure out, the more confused I am, any thoughts?

[Glim]

I ordered a spare a few months ago just to have on hand and it is gray. The originals are black. I ran with the gray one for a week just to make sure it worked if I needed it.

Part 0 221 504 465, 00002298688

I would wipe off the antisieze and if still rough - move the gray coil to another cylinder. NGK plugs do not require anti sieze, your plug(s) may not be grounding properly.

[surfariver]

Would you mind taking a peek at the gray one to see if there is a metal female connector inside that the plug clicks into?

The black ones had this but the gray one did not. After I cut away the rubber boot, I can't figure out what would actually keep the plug in contact with the coil.

Dealership and local shops don't have them in stock, hopefully they're coming in tomorrow.

[Glim]

Looks like it doesn't have a female connection, looks like a flat round metal piece that the top of the plug rests against.

[surfariver]

Thanks for looking, thats so weird the way it is designed. I wonder what keeps the connection if its just the two flat ends.

New part is coming tomorrow, I'll try it and I'll try to wipe the anti-sieze off and hopefully one or both of those things works.

[surfariver]

Alright, weird getting weirder. Today I realized I had something that could read codes. Boy, too bad I didnt think of this before.

While this ignition coil I was looking at was in #4, the error was showing #2! I swapped the ignition coil for #2 and #6 and put the old plugs back in #2. Then I got errors for #2 and #6 together. I then put the coil back on #2 and put another old plug back in #6 and I'm still getting errors for #2 and #6 so I've somehow spread the problem.

Taking it to the garage tomorrow AM unless I come up with some Christmas miracle this evening.

Am I safe to assume its not that I put the anti-seize on, since its only isolated to those 2 cylinders and didn't go away when I put the old plugs back in?

[Glim]

Clean off all dielectric grease from coils and plugs, retest.

Still an error? Swap your 1 and 2 coils see if the fault moves to 1.

[surfariver]

Took it to a garage, they finished it up in 30 minutes. Replaced the AutoZone NGK plugs I got with OEM BMW ones (really?) and replaced the #2 coil. Said that a bad ground (anti-seize?) can burn the coil up.

Labor $30
Coil $80
Plugs $120

Plus the coil I bought to replace the one that wasn't actually fried $60

Plus the stuff I bought at AutoZone for the job I tried to do myself $140

Total cost of changing my plugs: $430.

Probably still cheaper than going to the dealership! Should we pull the "Use Anti-Seize" off of the spark plug thread or do ya'll think it was some other kind of user error that casued this?

[Glim]

Glad you got it sorted out

The spark plug DIY thread covers it if you follow along through the long long thread, ngk plugs do not require antisieze, if you are going to use it - use copper or it may cause grounding issues, using antisieze torque to 17 instead of 22 lbs.