Churchill

Did the spark plug part of the 40K service today. Very easy DIY that even beginners should not feel intimidated doing. If you can change your oil, you can do this. Should take 1-3 hours depending on your experience level. You'll need a torx set, a torque wrench, assortment of extensions, lift, or floor jack and stands. Basic stuff.

1. Loosen the rear lug nuts, raise the back of the car, and remove the wheels. If you have a lift you don't need to take off the wheels, but I was working with a floor jack so they came off.

2. Each side has two heat shields, each of which is held on with two torx bolts. Remove the heat shields. This is what's under the shields:



3. You'll see an electrical connector on each cylinder plugged into a coil-on-plug assembly. The connectors have a tab that has to be depressed (they click so you know you've released them). Push them off the coils. The COP on the left in this pic has been unplugged and removed with the electrical connector dangling, and the right one is still plugged in:



4. Remove the torx bolt on each COP.

5. Remove the coils by pulling them out. They're held in by a three-layer silicone dust shield and slide out with a little pressure. This is what they look like:



6. Now remove the plugs. Each cylinder will need a different combo of extensions as you have to maneuver around the plumbing that's in the way. A universal joint is key here. You want to use extensions to get your ratchet into the wheel well, away from where it'll get tangled up in plumbing and your knuckles destroyed.



This is looking in on a plug:



Here's what my 41K-mile plugs looked like. Textbook example of a healthy plug from a well-running motor. Really don't even need to be changed.



7. Install the new plugs. Be careful as you're inserting them into the heads not to bang up the tips of the plugs, which have a specific gap. Start turning them by hand, not with a ratchet, so you don't cross-thread them. Torque to 22 ft-lbs. I believe the factory says not to use anti-seize on the threads, but I used a very tiny dab. Pretty sure the factory says not to use it because too many people slather on too much and end up over-torquing the plugs.

8. Reinstall the coils and seat them firmly in the heads. Re-connect the electrical connectors (they will make a faint click). Reinstall the single torx bolt for each. Just snug them up -- do not overtighten. These are small fine-thread fasteners threaded into soft aluminum and you can strip them easily.

9. Reinstall heat shields. Like the COP torx bolts, do not overtighten these. Just snug them up. Reinstall wheels. Go for a spin. Enjoy knowing you didn't pay the dealer $1K for 90 minutes of fun work.

KBell

Excellent DIY!

Duke I

Nice write up and pics. Thanks.

Do you mind sharing pics of the tools especially the extensions and the universal joints or wabble gizmos, etc.?

How did you get around the piping to the coil pack on the left of your pictures?

Thanks.

Churchill

I didn't take pics of that stuff, but it'll take you a second to figure out. For most of them what worked was this assembly: 1) the spark plug socket, 2) a ~3" extension that reached the opening of the head, 3) a universal joint, 4) a long extension that allowed me to work the ratchet from the wheel well.

Mlbraptor

Excellent. Thanks.

teambell

Great write up!

CSK 911 C4S

Great Sunday fun.

Needsdecaf

Very nice, thanks!

Money2536 did a video on his GT3...he did not remove the wheels which I am sure makes it harder.

duxsi

Great write up - thanks.
Did you re-gap your plugs?

mtgadbois

My $.02. If you use ANY anti-seize do not use a torque wrench. Instead do a "tight + a tug." I cracked 2 plugs on my Boxster using a torque wrench. Did not lose any doing it the old way.

Needsdecaf

+1. This is why they tell you not to use anti sieze compound. Messes up the torque wrench reading.

Churchill

Heh -- the "tight + tug" actually was the old way, at least back when I was working regularly on 911's, because the plugs had a crush washer. You'd hand-tighten till you felt the crush washer engage, and then go 1/4 turn more (IIRC). No torque wrench involved. I've been using a very small dab of anti-seize on spark plug threads for 20 years and have never had a problem. Where people run into trouble is when they use too much....

TK11069

I'm in the middle of this now. How did you deal with the driver side front plug and that bracket in the way?

CSK 911 C4S

It's just held on with one bolt ...remove it ...... then it moves out of the way.

It must be a part of the head light leveling system for the xenon lights or something to do with PDCC since some cars have it and some do not.

Churchill

That is the toughest one to get out, and my car does have PDDC and plumbing there. IIRC, I used a universal joint at the opening (by the surface of the head, if that makes sense) and then ran a long extension out through the plumbing into the wheel well. It doesn't work to try to put a ratchet directly over the opening -- too much stuff in the way.