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Replacing Spark Plugs on your Porsche 911 Carrera
 
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Pelican Technical Article:

Replacing Spark Plugs on your Porsche 911 Carrera

Time:

2 hours2 hrs

Tab:

$20

Talent:

**

Tools:

Spark plug wrench

Applicable Models:

Porsche 996 Carrera models (1999-05)
Porsche 997 Carrera models (2005-12)

Parts Required:

Spark plugs, spark plug tubes

Hot Tip:

Don't use anti-seize on the plugs when installing

Performance Gain:

Cleaner, better running engine

Complementary Modification:

Replace spark plug tubes

The replacement of your spark plugs and spark plug wires (where applicable) is a basic tune-up procedure for just about any car on the road. I recommend replacing your spark plugs every 10,000 miles, or about once a year. In reality, you can probably go longer than that; however, you never really quite know how long the plugs are going to last, or you may forget to replace them if you don't set up a yearly schedule.

With the introduction of the Boxster / Carrera engine, Porsche eliminated the use of spark plug wires by integrating six small spark plug coils that sit on top of each spark plug. While this configuration may be a bit more expensive than the typical single coil, single capacitive discharge box configuration, it makes the car's ignition system more reliable by removing a component that constantly wears out and fails (spark plug wires). It's a pretty cool setup not commonly found on older cars. As manufacturing components have become increasingly inexpensive, ignition setups like these have become more common.

Begin by prepping the car. The only thing that you really need to do is make sure that the car is cold. If you try to remove or install spark plugs in a hot car, then you may encounter problems with the spark plugs gumming up or damaging the relatively delicate threads in the aluminum cylinder head. Make sure that the car is cold or, at the bare minimum, only slightly warm to the touch.

Jack up the car (Pelican Technical Article: Jacking Up Your Porsche 911 Carrera). While you do not need to remove the wheels to change your plugs it will give you a little more room to move if you do. There are shields protecting the heads that will need to be removed on both sides of the engine before you can get access to the coils. On the 996 Carreras each cover is held on place by 2 10mm bolts, on the 997s they have changed to 8mm Torxs. Simply remove them and place them aside.

For each coil, remove the two bolts that attach it to the engine. Unplug the coil wire harness. Then simply remove the coil/plug assembly and place it off to the side. All of the coils are the same, so it doesn't matter which cylinder bank it came from, unless you are specifically trying to troubleshoot a bad coil fault code that was displayed by the main computer.

With the coil assembly removed, you should be able to look down the hole and see the spark plug hiding in there. If the tube has oil in it, it may have cracked or become contaminated. Replace it with a new one (see Figure 3 and also Figure 6 of Pelican Technical Article: Porsche 911 Carrera Camshaft Swap and Valve Train Repair).

Spark plug removal is easy. You just need the right spark plug wrench. I have one that I love--it's a spark plug socket with a rubber insert that catches the plug and also has a built-in swivel on the attachment end. These wrenches are readily available from the tools section of PelicanParts.com. This tool is especially useful when trying to remove plugs in hard-to-reach places.

Using a breaker bar, grip the plug and turn it counterclockwise until it is loose. Then pull out your tool and grab the plug. When the plug comes out, you may want to take a close look at it. The spark plug is really the best way to visually "see" what is going on inside your combustion chamber.

Install your new plugs using a torque wrench to measure the amount of torque applied to the plug. This is very important, as it is easy to over- or under-tighten spark plugs. Make sure that the plug is firmly seated in your spark plug socket, as it is very easy to insert the plug into the head and have it cross-thread. This means that the threads of the spark plug don't mesh properly with the ones in the head, instead choosing to "cut their own path." This damages the threads on the head, and in extreme cases, may destroy the threads in the cylinder head entirely. Trust me, you do not want this to happen. Proceed carefully and cautiously here.

Install each spark plug into the cylinder heads without using any anti-seize compound. Torque the spark plugs to 30 Nm (22 ft-lbs). I recently learned that Porsche published a bulletin indicating that it doesn't recommend using anti-seize compound on spark plugs for any of their engines (Porsche Technical Bulletin 9102, Group 2 identifier 2870). The bulletin applies retroactively to all models, and the theory is that the anti-seize tends to act as an electrical insulator between the plug and the cylinder head. This could have detrimental effect on the firing of the spark due to the loss of a good, consistent ground connection.

With the new plugs installed and tightened to the correct torque, you can replace the coils and reattach the coil connectors. When you're done, your engine should look back to normal and run perfectly.

Each cover is attached with 2 10mm bolts (red arrows) remove the bolts and cover to access the coils.
Figure 1

Each cover is attached with 2 10mm bolts (red arrows) remove the bolts and cover to access the coils.

Each spark plug has its own individual coil.
Figure 2

Each spark plug has its own individual coil. These are attached to the engine with two bolts (purple arrows). Remove each bolt and then disconnect the coil plug harness (green arrow). The coil should be able to be pulled from the engine once loose.

This particular photo shows an individual spark plug coil (inset).
Figure 3

This particular photo shows an individual spark plug coil (inset). The blue arrow shows the plug that powers the coil, and the orange arrow shows the mini-bellows that is part of the coil that seals the chamber and keeps dirt and debris out. Be sure that you inspect the coil packs for cracks, particularly if the car has been driven on roads covered with salt. These coil packs can corrode, crank, and then cause misfires.

I like to use a swivel-socket spark plug removal tool from Craftsman.
Figure 4

I like to use a swivel-socket spark plug removal tool from Craftsman. This tool is great for getting around bends and into hard-to-reach places. If you have a leaky seal on your valve cover, there is the opportunity for the spark plug holes to fill up with oil. When you pull out the spark plug connector/coil combo, you may find that it is contaminated with engine oil. If this is the case, then you should replace the spark plug tubes (yellow arrow, Carrera 996 Picture 2004:). These are plastic liners that seal the internals of the engine from the spark plug chamber. Use a pair of needle-nose pliers and simply grab the tube and pull it out of the hole. Later 997 Carreras (Picture 2008:) don't have tubes, but O-rings in the camshafts housings that should be inspected at this time.

In the photo inset, you can see an unusual spark plug with all four of its electrodes eaten away (red arrow).
Figure 5

In the photo inset, you can see an unusual spark plug with all four of its electrodes eaten away (red arrow). I would hazard a guess that this plug was improperly plated from the factory, and as it progressed through its life, the repeated sparking slowly ate away at the electrodes until they were gone. A plug in this condition would misfire often (if at all) and would generate poor performance for this particular cylinder. Surprisingly enough, none of the rest of the spark plugs in this set exhibited this type of damage. This is what leads me to believe it was defective from the manufacturer. On the right is shown a brand new Bosch Platinum spark plug. Spark plugs have varied over the years as engines have been changed slightly due to smog regulations. The important thing to remember is to get the proper ones for your car, otherwise you may encounter odd ignition problems (they are scaled by both electrode type and also by heat range). Spark plugs are cheap--I would go with a brand name like Bosch or NGK and avoid the no-name brands.

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Comments and Suggestions:
Drummerboy Comments: Thought I would put my experiences into the fold . Just replaced six coil packs on 997 3.8S . I had replaced spark plugs about 9 months ago so this was a similar job of course . Just like to say it can be done without removing exhausts . It helps if you are a cortortionist especially if you're doing it on your back . It's very fiddly to say the least and if you have big hands even worse . It helps to remove the sensor plugs in the head this will give slightly more room . Wheels really should come off as you will be at all sorts of angles on the floor some access is better to the rear of the underside of the car and dome from the other end of the engine . It took me just over 3 hours to do all six and I'm quite a competent mechanic on 997s
anyway . . I take my hat off to anyone who can jack up remove wheels heat shields 6 coils etc in 1.5 hours . Maybe on a ramp I could ? But it is possible without removing exhaust and earth leads for that matter . Very satisfying when finished and gets easier each time . Other jobs done recently include flange gaskets and bolts ,starter,alternator starter lead which fails after a while making starting a problem when hot ,front rad cleaning,brake fluid change ,sat nav aerial , rear shocks, new firs gear replace ,clutch and dyslexic mass flywheel . And that's all in the last year ! Only done 67,000 miles . Costing a fortune . Thanks to pelican for very informitive articles .
November 17, 2016
  Followup from the Pelican Staff: Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
hunter Comments: Did my '07 997S yesterday. Totally do-able without removing the mufflers, with a lot of patience. Make sure the engine is completely cold. To get to the torx bolts securing right rear coil, had to use a small torx bit without a ratchet receiver base see pic. These bits have a shank that you can get a small open-end wrench around to get to the top bolt. Another tip: replace the connectors and dust boots before you secure the coils, this will give you more room to maneuver. Also, be aware that there is no audible or tactile "click" when the plug tube goes over the spark plug. At first I thought it was not seating properly, but with a plug tube out, you can see the plug tip just sits in the tube against the connector.
November 12, 2016
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
Aly Comments: Just wanted to put in a few comments. I was able to replace my 2006 997 plugs without removing the mufflers, but could not replace the two rear cylinders spark plugs. There was no way to get in to loosen the TORX head bolts that held on the coil and to get in a spark plug socket to remove the plug because of the mufflers. So I have to take out the mufflers to replace the rear two plugs. I had the rear wheel removed and the car jacked up off the floor, one side at a time. I was able to do the front engine 4 plugs, where the middle two were more difficult.
You have to slide the rubber covers over the coil connector up clear of the connector, then squeeze the connector locking clip and carefully pull off the connector. Do this before removing the TORX bolts. It was difficult getting to one of the TORX bolts on the middle coils, but using a universal joint attached to the TORX socket and then attaching a longer ratchet extension, it could be loosened even though it should not be that tight holding on the plastic body coil. I tried to get to the back engine coils, but could not see how to get my 1.5" TORX socket with an U-joint in there to loosen it. It barely fit and won't turn at a right angle.
I used DENSO IK22 Iridium plugs that were spec'd by DENSO for the car. The old plugs were the BOSCH originals, but I disagree with Nick that the engine was designed for the BOSCH. The plugs are designed for the engine and Iridium is a better metal to use for the plug tip, and does not need four ground electrodes for a reliable spark. Because it is so difficult to replace them, use the more expensive plugs so you don't have to replace them again.
I am going to try to get out the mufflers without removing the bumper, or at least drop them down to get to the coils. There may be a way to get them out without removing them, but I could not see it. Maybe if the car is up on a rack one could find a way, but jacked up on the floor and trying from underneath is so inconvenient to try.

September 9, 2016
  Followup from the Pelican Staff: I use parts Porsche recommends, has kept me out of trouble my entire automotive career.

I have also not had to remove the mufflers, could be a technique thing.

Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
BKSanders Comments: Follow up: Never mind. I got off my lazy but and found out they need a 5 mm hex drive. Just finished in about 1.5 hours. There's no way you can do this with the mufflers attached. Save yourself time and headache; take the 30-45 minutes to take off the bumper and remove the mufflers; band clamps and three bolts on each side. It will allow better access to the coils that are obstructed by the muffler brackets. Oh, and go to your local auto parts store and buy a magnetic spark plug socket; it's more precise, holds and lines up the spark plug with ease. Cheers.
June 12, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
BKSanders Comments: Quick clarification: Confirm that a torx head is required for removing the two bolts on the coil; and what size? Thanks. Going to tackle this sometime this week.
June 11, 2016
  Followup from the Pelican Staff: Coil is 5mm Allen. - Nick at Pelican Parts  
markp92692 Comments: As a first timer myself, it took 4+ hours of non-stressed installation, over the course of 1 full day. I was concerned this was over my head, but after removing in order, Tires, Bumper, Heat shield and mufflers, I had reasonable access with a swivel socket and common tools. Great sense of accomplishment, my back up plan was - if all starts to go wrong, stop and tow to my local shop.
May 13, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
w2rivers Comments: What about using iridium plugs in the 996?
May 10, 2016
  Followup from the Pelican Staff: I would stick with the regular plugs BKR6EKUB .

Engine is designed to run with them. - Nick at Pelican Parts
 
rdrngrp Comments: You will need more than a spark plug socket and two hours. It took me way too long and various torx and extensions. Plug #4 is by far the most difficult but #3 is no parade either.
This task will now be known as Ferdinand's Revenge.
April 17, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Nutbutt Comments: I have a 2009 911, 997.2, Do I need to remove the exhaust or manifold to change the plugs ??
April 15, 2016
  Followup from the Pelican Staff: No. - Nick at Pelican Parts  
Craig Comments: I have a 2004 996 4S. I got MSD plugs and they only have one electrode. Is this an issue? Should I return them for the 4 electrode type?
April 14, 2016
  Followup from the Pelican Staff: Check with MSD or our parts specialists. I only use the factory plugs. I have no experience with the MSD plugs. To be sure, Give our parts specialists a call at 1-310-626-8765
- Nick at Pelican Parts
 
ShadeTreeMechanic Comments: It's definitely doable - even w/o removing any exhaust components. I'm a novice and accomplished this feat, just be patient, drink beer, and play some music helps pacify the frustration. Good luck!
February 21, 2016
  Followup from the Pelican Staff: Thanks for the info and feedback. Appreciate it. - Nick at Pelican Parts  
Jim Comments: 2003; 966; 3.6- question- when should the power/coil packs be replaced?
February 9, 2016
  Followup from the Pelican Staff: When they fail or are damaged. No maintenance is recommended by Porsche other than that.- Nick at Pelican Parts  
fishermen Comments: i went to remove one spark plug and now it came off in the cover whats the best way to get it is a 1982 3.0 911 sc f
January 18, 2016
  Followup from the Pelican Staff: What came off in the cover? Please explain your problem in more detail. - Nick at Pelican Parts  
scott Comments: Nick, I did get the #4 coil completed
I already had the bumper / heat shield / mufflers off modded ones coming !!
so I took the last section of shield 4 nuts off and got the finger room
I needed

spent more time trying to attach the coil to it's lead than what took to remove & install
the last piece of shielding
August 24, 2015
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
 
tony c. Comments: HI, 2004 911, 123000 miles, not starting on first ignition turn , starts on 2nd turn ,replace spark plugs, ignition coils, filter, on first turn rough start on 2nd starts and runs good... ths
August 21, 2015
  Followup from the Pelican Staff: I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
 
scott Comments: I'm doing this right now and encountering some difficulty...
Drivers side went reasonably well, but I'm stuck on the #4 coil
pack connection
One trick is to use 2 spark plug sockets, one with the foam for
removal and one without for installation..allows for a little more 'feel'
August 18, 2015
  Followup from the Pelican Staff: Did you get #4 coil out?

Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community. - Nick at Pelican Parts
 
Kay Comments: What are the torque specs for the 2 bolts for the spark plug cover?
July 15, 2015
  Followup from the Pelican Staff: For 996: (M6 x 25) to 10 Nm (7.5 ftlb.) - Nick at Pelican Parts  
whm Comments: I have 06 c2 is it possible to change the plugs without the removal of the headers and muffler? thanks
May 9, 2015
  Followup from the Pelican Staff: Yes definitely, requires a bit more patience and a good selection of different length extensions with wobble capability to get the job done on the passenger side of the car especially for cyls 4 and 5. I say go for it. I like to use a 3 inch wobbly extension, a stubby 1 inch extension, a spark plug socket and a 12" long ratchet with wobbly head. Removing the rear wheels also really helps provide access. - Casey at Pelican Parts  
Randy G. Comments: It took time and dexterity to renew these six spark plugs on my '02 911 turbo, safety is paramount to do this job properly, with a small space to work on between firewalls and engine, it needs a lot of patience to install plugs. A flexible joint spark plug socket wrench is a must. As mention threading back these plugs, if necessary use a fuel line hose to hold plug to initially engage thread to prevent cross-threading, then tightened to specified torque22ftlbsand you don't want to over tightened. Lastly make sure coil packs were connected properly tight. Thank you pelican for this valuable info.
March 29, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
RobScott Comments: I'm trying this for the first time tomorrow weather permitting on my 2002 3.6 C2. Wish me luck then!
September 26, 2014
  Followup from the Pelican Staff: Let us know how it works out. - Nick at Pelican Parts  
Laz Comments: Just as a heads up, my 2002 Carrera does not utilize the spark plug tubes - it has the O-rings in the camshaft housing.
September 24, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
VeloYelo Comments: What is the spark plug gap? for a 997.1 GT3?
July 9, 2014
  Followup from the Pelican Staff: You do not have to adjust gap on multi-electrode plugs. So there is no published spec for gap. - Nick at Pelican Parts  
OldEnoughToKnowBetter Comments: I'm sure most know this, but just in case ...
Something an old mechanic taught me years ago. Get a 5.5" length of 3/8" fuel line hose. Push the hose over the top of the spark plug and thread the plug in using the hose as a grip. Almost guaranteed to not cross threat the plug.
You can do this whole job ... be patient and trust the force !!!
May 23, 2014
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Bill Comments: I recently replaced all 6 plugs and coils in my 997.1 4S. It seems to lose power midrange and then the engine light see workshop light comes on. Is there a burn in period after replacement? I have run the car twice since replacement and it's happened both times. I disconnect the battery after I drive
April 7, 2014
  Followup from the Pelican Staff: No burn in period. I would start by checking the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.
- Nick at Pelican Parts
 
Steve Comments: Thanks for all the responses but what is the gap for the plugs
April 5, 2014
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
 
Steve Comments: I want to check the drive belt, replace the plugs, air filter, oil filter and oil on my 2010 porsche 911 C4s Is everything similar to the earlier 997's ?
Steve
April 2, 2014
  Followup from the Pelican Staff: It is similar. There may be minor differences. - Nick at Pelican Parts  
jjb7 Comments: I just did this job for the first time. It requires removal of the muffler, and still a tight fit due to the bracket that blocks one plug on each side. This article is misleading by having the engine out of the car and no bracket. 10K mile plugs? Spend a little more and get iridiums 100K in applicable. I upset that the Bosch's are only rated for 30K. finally, Coil On Plug technology is to get a better spark at high rpm, increasing HP and MPG.
March 24, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
johan6504 Comments: Just completed this job, not the easiest but doable. Completed in about 1.5 hours...
March 23, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
art Comments: you might want to change the cost of this job since you charge a lot more than that for plugs...
February 20, 2014
  Followup from the Pelican Staff: Thanks, I asked the Pelican Team to update the cost. - Nick at Pelican Parts  
Rbj Comments: This task is made to sound straightforward and easy in the article. In reality changing out the plugs and coils is a PITA job. The rear ones on each side are very difficult to get at and require significant dexterity and patience. Reattaching the coil pack connectors for these two locations is the most difficult step in the process. I will sell the car before i have to endure this level of angst again!!!
February 13, 2014
  Followup from the Pelican Staff: Thanks for the feedback. We appreciate it. - Nick at Pelican Parts  
RED Comments: Very Helpful Thank You!!! it was easier then i thought. The Passenger rear one was the one that gave me most trouble, but all and all very doable job. I get stressed easy i guess an would advise anyone to take your time, don't rush. A lot can go wrong if you start pulling and pushing. To be honest take a day to do this, this way you are not pressed for time its not NASCAR. Hardest for me was jacking the car up correctly and safely, its very low and its hard to get a good jack under it. I just kept telling myself to slow down and not make this more expensive then it already is. PS most likely your PSM FAILURE will pop on when you reconnect the battery, don't worry drive 20miles or so it will go off. Again thank you so so much could't have done it without this post here. My level of expertise is NOVICE for those wondering. Oil separator next!
January 29, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
firmsi Comments: poor TTimmy - it took me 2 hrs to replace the coil packs on my997 - this article mentions nothing about how it is virtually imposible in the sapce to have on the car!
November 17, 2013
  Followup from the Pelican Staff: It is a tough one. Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
TTimmy Comments: As a first timer it took me over four hours to complete this job. I'm sure it will go quicker next time as I have figured out how to contort my hands to get into the tight spots. The rear plugs were the worst. I found it worked best to work front to rear, removing the coils first to maximize the amount of space to work. I think the most important point for a newbie is knowing that it's not impossible, it can be done - just takes some time!
November 9, 2013
  Followup from the Pelican Staff: Thanks for the additional Info. We appreciate it.
- Nick at Pelican Parts
 

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