Spark Plug Change 2.0

[whadapanch]

I wanted to create this thread as a summary to the previous threads that were already created. I couldn't have done this job as efficiently without the help of the previous threads. However, they became extremely lengthy to read through all the posts and I thought a summarized thread of the past knowledge with a little of my own would be beneficial. Thank you to all the previous posters input for making this job easier. I would suggest reading the first part of the previous threads to take advantage of the pictures, and then consulting this thread instead of reading through 17-20 pages to get the below information.

If you’re like me, you’re proud to have the first and last production NA V8 M3 and are in for the long haul past the free maintenance. My 2009 E90 was purchased certified pre-owned at 24K miles. My car is now at 44K and my 4 year free maintenance is over. Before performing the spark plug change, I confirmed through the stealership that they had NOT changed the spark plugs during my free maintenance during my several trips for planned free maintenance between 24K and 44K. In fact, they mentioned that changing the spark plugs is not necessary in their certified pre owned service. So they didn’t change at 24K which makes sense, but they also didn’t change through 44K in which I had brought my car in for planned service numerous times. My car wasn’t running bad by any means, I simply changed the plugs because it was well over the BMW specified 37K and I determined BMW hadn’t changed the plugs even thought they had plenty of chances.

Tools Necessary
These tools are what I used to get the job done. There are certainly other tools that I tried and helped, but I wouldn’t consider necessary for an efficient job. I have to say, after reading previous posts and performing the job, the tool designed by TxStig in the previous post is certainly the right tool for the job. However, I got to the party late and didn’t get his tool. It looks like his tool works great given the weak BMW design that TxStig had to work with. It seems to me, those plastic fixtures at the top of the coil are just too weak to use. You need the TxStig tool to decrease your chance of snapping them off. However, if you don’t have one, there is an alternative method that is free and works very well. Again, this wasn’t my idea, it was from previous posters. Thank you again to the previous posters who came up with the ideas that ultimately helped create this summarized thread. The below are numbered and correspond to my posted picture.

1. The previous threads! I printed them all out and used them as bathroom reading. I performed the job and will be letting you know what worked for me.

2. Certainly not necessary, but makes the work go by faster.

3. A socket wrench and a torque wrench. I used 3/8” drive for both. My torque wrench is fairly cheap. If you don’t consider yourself to have good judgment on torque by feel, I would suggest a premium torque wrench. 23 Nm is spec, but 28 Nm was used in previous posts as well.

4. Two types of 5/8” long sockets help for the spark plugs. One designed for spark plugs that have a rubber insert to grab the plug as you pull it out. The other design should be regular without the rubber insert for when you tighten down the new plugs and don’t want it to grab. If you use the rubber insert sockets to tighten, the extensions and sockets separate when you try to pull off the plug, so it’s easier to pull off the plug with the normal non rubber sockets. Depending on your intake, you may need a 10mm socket and allen wrenches.

5. Extensions and knuckle. I didn’t use the knuckle tool much to perform the job, but I would say it’s handy if you don’t have a variety of extensions. Various sized extensions make the job easier. I would say a 3” and a 6” are enough. I would have liked to have two 3” extensions but I managed without. The extensions and sockets help a lot if they are the design that can swivel. That’s why two 3” are better than one 6”. When you connect the extensions and sockets together, you should be able to connect them half way that allows for the connections to swivel and then push them all the way in for a rigid non swivel connection. This helps “snake” them in and out of the plugs nearest the firewall.

6. You need eight spark plugs. If you didn’t know that, take the car to the dealership. OEM plugs are NGK LKR8AP. They can be found from various vendors under part 4471. The stealership wants $18-19 a pop. Autozone, Oreilly’s etc. want about $13-14. FTW, Rockauto.com has them for $9-10 per plug. BMW stealerships usually have them on hand for instant availability. Autozone, Oreilly’s will usually have them ordered factory direct. I bought my plugs online from RockAuto on a Friday after business hours and they were shipped by the following Tuesday when I got home from work. Shipping cost was modest/acceptable.

7. THE Tool. If you don’t have a BMW or TxStig tool, this is not just the next best thing, but possibly the best thing. I did not have the TxStig tool so I have no way of comparing. Previous posts suggested a coat hanger or a CAT-5 cable in place of specific tools. I tried both. The CAT-5 works well for these reasons.

The plastic sheathing is less damaging and easier to grip than the coat hanger.
The CAT-5 can be looped around the coil and then twisted to create a noose gripping force. (picture below)
The CAT-5 can be looped around the base of the coil easily which allows for less chance of breaking the coil. The BMW designed grip point is very susceptible of breaking.
The CAT-5 works very well in the confined spaces. It’s flexible and can be manipulated onto the coil in the tight spaces by the firewall.

8. Gap tool. I have a cheap tool, there are better ones out there. .032 inches is the necessary gap. In short, I took readings on the new plugs and they were all fairly consistent. I took my 44K plug gaps and new plug gaps in a picture below. I didn't fill in two of the cylinders as I waited until the end to do those before I took the picture. My gap readings are misleading because of the cheap tool. However, they are consistent in the sense that I took both the old and new plug readings with the same tool. The OEM plugs are not like an old school plug. Old school plugs have a profile with a flat lead. The OEM plugs have a crescent/semicircle profile (picture below) which creates an equal distance from any point on the lead to the center. Due to this, I feel as though my gap tool is reading gaps shorter than actual. I compared the gaps on my used plugs and the new plugs. See below picture. For $10 a pop, I concluded that the gaps were consistent from the factory and that I wasn’t going to chance scarring/scuffing the fancy pants PLATINUM coating with trying to adjust the gaps. The car is running well with no adjustments from factory. The old plugs were noticeable all over the place in gap distance compared to the new factory plugs which indicates 44K of miles changed the gaps quite a bit.

9. Flashlight.

10. Allen wrenches depending on if your intake is OEM or aftermarket. I had an aftermarket that required it.

11. Flat head screw driver depending on your intake. I needed a flat head to loosen the intake.

Spark Plug Prep Work
I did not use mechanic gloves as my hands are fairly large and you need every bit of space you can to do the work near the firewall. Gloves simply didn’t allow for my hands to get where I needed them to be.

1. Remove your air filter/intake assembly. Disconnect the tube that connects into your intake. I found that it can be pulled over the plenum and snapped between the plenum and hood to remain out of the way.

2. Plenum removal is not necessary. If you want more space to work, go for it.

3. Coolant reservoir does not need to be moved extensively. I took the two 10mm bolts off and moved the reservoir slightly to help take the plug cover off. However, you don’t have to flip it or pull it far from the mounting. Be sure to replace the anchor point into the rubber grommet at the base of the reservoir when replacing. There are sensitive wires at the base, make sure they aren’t pinched when you reinstall.

4. Remove the spark plug covers. Each spark plug cover has two mounting points that just need pulling force. Use your hands to pull up on each end until the cover pops out of the rubber grommet. The driver’s side has a hose connected to it that needs to be popped out before removal. The passenger side removal is easier if you loosen the coolant reservoir from its mounting points.

Passenger Side Coil removal (hardest)
I suggest starting with the most easily accessible coil first to get a feel for what it takes to remove a coil and then remove the firewall coil next to get the hardest one done while you have your energy. I chose to remove 3 of the 4 coil/plugs so that I had a factory reference coil/plug to look at when installing the coil after the new ones. I chose to leave the easiest coil/plug for last.

1. Unplug the connections from all the coils. Just push the tab down and push/pull out much like you would with an Ethernet cable. Make note of the orientation/direction of the coils. On the passenger side, they are all oriented in the same direction.

2. When pulling the coils out, I had success with twisting the plugs slightly by hand slightly left and right while trying to pull out. The front plugs can be pulled by your hand only, if you’re a man. After loosening as much as you can by hand, loop the CAT-5 cable under the coil. Don’t settle for just underneath the electrical connection. I used a blunt object to stuff the Ethernet as far below the coil head as possible to distribute the pulling force as evenly as possible. As pictured below, twist the CAT-5 until you strangle the coil and begin pulling up. The amount of force necessary is above moderate, but not full strength. After a couple of coils, I was less worried with breaking the coil head and more concerned with the surrounding wiring being damaged. Unlike the BMW connection at the top, the entire head underneath the electrical connection is fairly robust. Use good judgment! You may have to switch between loosening with your hand and strangling with the CAT-5 a couple of times.

3. Passenger side firewall. This coil can’t be pulled easily at an angle. I suggest fishing the CAT-5 through the aluminum brace and various wiring so that you can pull on the coil as close to directly up as possible. I used one hand on the CAT-5 to pull up while my other hand held the coil and helped pull.

4. Once the passenger coils unseat, they can be pulled out by pushing surrounding cabling/tubing aside. Make note of the condition of the coils and set aside. I like to replace everything where it came from. From previous posts, it seems these coils are all interchangeable in the event you have some snapped coil heads that you want to put towards the front of the car.

Passenger side plug removal.
Once the coils are removed, you can unscrew the plugs. I found the plugs being removed from factory spec were pretty tight but manageable. They certainly unscrew with a little more resistance than when putting in the new ones. Once the initial break happens with the socket wrench, you should be able to unscrew by hand strength.

1. Use the 5/8” long socket with the rubberized insert. Connect an extension and use the socket wrench. The back two require more imagination with the extensions. You can drop the socket and extensions in piece by piece and snap them all together as you go. Make note that once you snap the rubberized socket onto the plug, it isn’t coming out until you unscrew the plug. You can’t pull it off of the seated plug with the extensions as the connections will break before the socket breaks from the plug. Clear as mud?

2. Passenger side firewall. There are some wires and tubing that get in the way, but you can move them enough to get extensions in. When the plug unscrews, you will have to make use of the swivel function of the sockets and extensions as noted in the tools necessary section. You can’t pull out the tool string in a rigid configuration. The socket and extension connections should break to a point where they swivel but still remain connected to each other. This allows you to snake the plug out with the tool string.

Driver side coil removal
Pretty much the same as the passenger side, but slightly easier. There is more exposed sensitive wiring on this side to look out for. The fire wall plug on the Driver side is different from all the others. It is positioned with the electrical connection facing directly towards the fire wall as opposed to the all the others which are pointed more towards the exhaust. When the coils are removed, you will notice there are tabs that extend from the heads that show where the electrical connection of the coil should be oriented.

Driver side plug removal
Pretty much the same as the passenger side, but slightly easier. Keep your extension as centralized as possible while you are breaking the plug connections. I gapped and inspected all my old plugs. I found that the gaps varied greatly from .024 to .032 using my cheap tool. The engine still ran great despite it. No knocking or engine shakes. I took a head on shot of the new spark plugs in an effort to further explain what I meant by my gap tool not being good for measuring these plugs. My gap tool would work for flat lead profiles. However, the crescent shape on the spark plug lead means my gap tool is measuring from the tips of the ends of the crescent shape to the apex of the center rod on the spark plug. However, the proper gap is from the apex of the center rod to the center of the crescent lead. Inaccessible by the gap tool. Any clearer?

Passenger and Driver Side Plug Installation
Use the same configuration of socket and extensions that worked best for the plug removal. Use the 5/8” socket WITHOUT the rubberized insert. This allows for you to pull off the tightened plug without separating your tool string. Check the gaps on your plugs and put your best ones into the firewall cylinders. Drop the plug into the hole and follow with your socket/extension assembly. Push and turn to get your socket onto plug. Use your hand to turn the assembly counter clockwise lightly until you feel the spark plug thread click down slightly. The thread is lined up and ready for hand tightening. Previous posts list 23 Nm as spec and up to 28 Nm for the plug tightening. This converts to 203 in/lbs to 248 in/lbs or 17 ft/lbs to 21 ft/lbs. I set my torque wrench to 28 Nm and found that this was just at my level of comfort when torqueing. I dialed down to 23 Nm and I felt like this was just tight enough. Just as soon as I started feeling like I was about to do damage, the torque wrench would click. The spark plug box will show a graphic telling you to hand tighten and then take a half turn with a wrench. I found that hand tight and then 23 Nm with the torque wrench led to much more than a half turn. USE GOOD JUDGMENT and/or a quality torque wrench.

Passenger and Driver side coil installation.
I chose to put the coils into the same cylinders that they came from. If you have coils with snapped heads, you might consider putting those in the easier cylinders. The coils need to be pushed in with the electrical connection oriented so that the notches on the head are lined up. The driver side firewall is oriented differently. I used the old plugs and pushed them into the coils to get a feel for how much force is necessary. In previous posts, for the firewall coils, it was suggested to use a pry bar to force the coil in and/or removing the plenum. I found this was not necessary. It’s all about getting your palm directly on the top of the coil so that your forearm is pressing directly down on your palm. If not your palm, the area just beneath your fingers. If you try to press in with your thumb or fingers, it’s hard/impossible. Even with the firewall cylinders, I was able to position my hand so that the coil was under the palm or main part of my hand. Once you get your hands set, make a forceful immediate push, not a gradual push. You’ll know when you got it seated, it pops in. If you didn’t feel anything, it’s not seated. If you left an old coil/spark plug untouched from the removal process, you can use it as a reference to make sure you are all the way seated.

Finishing steps
Once the coils are all replaced, snap the electrical connections back in. If you removed any wiring or tubing from a snap, replace it. Put the spark plug covers back. The Driver side will have some tubing to snap onto the top. The passenger side will need the coolant reservoir loosened to make way for the cover. Replace your intake.

Jerry Springer Final Thoughts
I let the car idle to running temperature to make sure the engine wasn’t shaking or throwing errors. I didn’t really notice anything in the driving, but I didn’t drive much. Just a short sprint outside the neighborhood. I did feel like the initial engine turnover may have been stronger/smoother. I would say this is definitely worth the money saved at the stealership. Previous posters listed $700-$800 total for a spark plug change. Even with the Beer, this was a quite a bit of mone

[thekurgan]

Apologies for just coming to this thread now. I'm wondering how you are measuring the gap with the disc type tool for these dual electrode plugs. NGK specifies only the wire tools, like in these photos. I too, found the gap different on maybe half of the received plugs but plugs removed from the engine after 20k miles had widened a bit.

[whadapanch]

Originally Posted by thekurgan

Apologies for just coming to this thread now. I'm wondering how you are measuring the gap with the disc type tool for these dual electrode plugs. NGK specifies only the wire tools, like in these photos. I too, found the gap different on maybe half of the received plugs but plugs removed from the engine after 20k miles had widened a bit.

No worries. I knew the disc tool was not correct for the measurements, but it was what I had on hand. As the disc type gap tool has a flat profile, it measured a shorter gap than actual since it is measuring from the tallest points between crescent shaped lead and the platinum tip. Therefore, my measurements are not accurate in gap size. They only show the general variance you can expect from any given new plug off the shelf as well as the variance in gaps from used plugs.

Thanks for the reply

[thekurgan]

Originally Posted by whadapanch

No worries. I knew the disc tool was not correct for the measurements, but it was what I had on hand. As the disc type gap tool has a flat profile, it measured a shorter gap than actual since it is measuring from the tallest points between crescent shaped lead and the platinum tip. Therefore, my measurements are not accurate in gap size. They only show the general variance you can expect from any given new plug off the shelf as well as the variance in gaps from used plugs.

Thanks for the reply

It's a great writeup, thanks for the detail and the beer reminder when it's time.

[aussiem3]

Very detailed write up and I am sure it will be an enormous resource to future DIY plug changes. By the way, I should have patented the use of CAT-5

http://www.m3post.com/forums/showpos...&postcount=332

[TxStig]

Pullers now available on Amazon:

http://www.amazon.com/gp/product/B00J9P0US4

http://www.amazon.com/gp/product/B00J9P0TYE

Cheers.

[IntegraXTR]

just did the spark plug change on my friend's M3 and it took about 1.5 hours, not hard at all. the cat 5 cable was a breeze.

the only tricky coil pack to remove was the passenger side one closest to the firewall. that and fitting a socket in to remove the plug. other than that, not too bad.