I am seeking information and pics as to how to remove components in sequence with ultimate task in replacing the sparkplugs. You can also send me feedback at harristh@comcast.net

 

Hi Harristh,

Sorry for the delay, just saw your post. We recently discussed this in a couple of threads. Maybe read through these, either Katie or I (or both) can help talk you through it.

Caution ahead of time - this is not a beginner's project. Only you know your mechanical skills. On a 1-5 scale I'd put this at a 3 to 4 in degree of difficulty. Not a lot of heavy work, but intricate and in very tight spaces. Very easy to lose things in places where you cannot see.

https://mbworld.org/forums/coupe-roa...ark-plugs.html

https://mbworld.org/forums/coupe-roa...ark-plugs.html

All the Best,
Acta

 

Thank you for your response. On the passenger side the 3 torx screws that hold the black piece (I think is for the crankcase ventilation) in the back are next to impossible to get access to. Did you remove the red rectangular bar with the yellow sticker to get access to them?


Also, the black wiring harness on the same side does not have a screw on top of it like yours. It has the torx screw underneath. What gives?

you can communicate with me on the phone with pics or feedback, my number is 780-502-8096 - Harris from north of Boston - thanks again!

 

Hi Harris,

Let's stay on the thread as it remains good info for others. I have limited time after this post and might not be able to get back to you until tomorrow (family stuff).

Regarding the breather tube on the passenger's side, there are 5 screws that hold it in place, not just the 3. They are marked item 15 in this pic:



There is a rubber sound proof cover on a piece of the fuel rail that partially obscures those 4 screws on the back end of that breather tube, but the sponge rubber is flexible and will yield w/o removing it if you have tools to get to the screws. If you are unable to get to them then, yes, remove the strut. It requires a little more disassembly but will give you a clearer shot at the 4 back screws.

On the black wiring harness, ignore the brass threaded fitting in the pics that you see in the other threads. It has nothing to do with the mounting hardware for the harness. There is a torx screw UNDERNEATH the harness block. It cannot be seen and you have to work tactically to find it with a flexible torx bit. It is easier to show the back of the screw to help you locate it by feel. The back of the screw is threaded into the lower heat shield of the turbos. Find the one I have circled here, then you'll know where to find the bolt head.



I think these are the answers to the Qs you have. Let's see if you progress from here and ask more on this thread if you need.

All the Best,

 

YOU need a copy of Mercedes WIS available on ebay for about 10 dollars so you can have the directions to do this job....... There are lots of things you will learn like all the small screws are 9nm torque............ ect ect.

 

Greetings Harris,

How are you carrying on? Have you begun the job or are you assessing it? There is a little more getting the harness block loose and away from the #1/2 coil pack, but wanted to stop where I did so you can assess the job that far. If you're good with the hidden screw under the harness block, and have the second screw out (both marked #19), then we need to tackle the third (#19) screw. It's, by far, the toughest and I can carry you through it if you need. Hopefully I didn't leave you stranded last evening...family Birthday celeb and I needed to be there.

Just let me know here.


Best,

Acta

 

I removed what was needed and the coils on the driver's side. However, it was really hard to pull the coils out with the boots. I mean extremely hard. I kept on spraying WD-40 around the boots. Finally, I got them out, but the front coil left boot broke on me. What a pain to get it out! I tell you! It broke into pieces in the hole, and it took me three hours to get all the pieces out. Eventually, I did and vacuumed the hole while the plug was still installed. I will get another boot tomorrow and the plugs and finish the driver's side. I will make sure that I put dielectric grease around the boot for easy fit and removal...
It seems to me that in the passenger side I will have to remove the strut. No way I can situate a torx 27 there to get the torx screws from the breather loose. I moved the computer out of its installation spot, by unplugging it the other day and the screws of the strut on that end become visible for removal...
Will keep you posted and thanks for your guidance and feedback! Much, much appreciated!

 

I like the NGK laser iridium plugs and I think Mercedes gets them from them and/or Bosch, but I will most likely get the Mercedes standard part, 000-159-05-00. I will ask if they are laser iridium. Thery all come pre-gapped, but I think the proper gap is 0.028". Let me know what you think or know...
Torquing the plugs to 23 nm equals 16.9 ft/lbs or 203 inch/lbs converted by a calc. with anti-seize lubricant applied and dielectric lubricant around the ignition coil rubber boots and on the boot end tip of the plug...

 

i got a copy on Ebay of a Mercedes WIS, but is unworkable. If you have any recommendations, let me know.

 

Hi Harris,

These are tricky. The files are huge, you have to adhere to the provider's min cach, memory and disk space. Mine is run on a virtual machine on a Windows 7 computer BC that's what it required. Also, many of these for sale are copies of copies of copies and some are corrupted.

 

Let me get this out of the way before going over to the passenger's side. Don't change the gap of an iridium plug. Use it as it comes. You can do more damage trying to change gaps. These are special use NGKs so they're mfgred for this platform. On my MB branded plugs, NGK with the NGK P/N is stamped on the metal body of the plug. I posted a pic of this plug in one of the threads above.

On torque. Here is the recommended torque for plugs with a compression washer and threaded into an aluminum head. You are at 16.9 lb-ft, the range is 10.8 to 14.5, but since you put Anti seize on the thread, this constitutes a lubricated thread. Lubricating threads add 20% to 25% to the CLAMPING FORCE of the thread, so you are realistically at 20.28 +++lb ft. This is way too tight, especially in aluminum. With anti seize you want to subtract 20%, so you should have set the torque wrench at 11.6 ft lbs. You might not own the car for the next plug change but if mileage/years are followed, the next change will likely be a tough one. So, if you haven't put these plugs in yet, PLEASE don't go with 16.9 and lubricated threads.


https://www.antiseize.com/PDFs/torqu...ifications.pdf

 

On the passenger's side YES, remove the strut if you need. It will give you more room to remove the breather covering the 3/4 ignition coils. One caution on unplugging the ECU - do not open the driver's door or the hatch. This wakes up the canbus and it will go through a diagnostic and set some U-Codes with the ECU missing in the network. I personally leave it plugged in but still don't enter the car through the driver's door. Instead, I always put the driver's/ passenger's windows down if I need to reach in for anything.

For the large harness block there is one more torx bolt to get it to move (a total of 3). This one is pretty hidden and will require some more disassembly. You need to remove the passenger's side air intake tube that goes from the right side air filter to the right side turbo. When you do, it "kinda" reveals the third screw. It can be seen if you part the left and right air charge tubes that come out of the turbos heading for the intercoolers. Here is a pic of the screw (like it'll do much good):



Here is a wrench on the bolt and it should make it a little clearer:



Once this screw is out the harness block will move for you.

Once it does, the next challenge is freeing up some of the branch harnesses. AMG did quite a job bolting down this motor! There are 3 tie wraps. Cut all 3 then you can get the 3/4 coil unplugged.

The yellow one wraps around the harness on the strut. You might have done that one already. The red one wraps around the 3/4 coil harness connector. You will not be able to get that connector released until you cut this tie wrap. The blue one is in close proximity to the red one and holds the fuel return to the harness (so there is no movement. It's important to get at least two of the 3 back in place. The first one to the harness clamp on the strut is less important, but I put it back anyway.




Some insight about tools. I've been wrenching for 40+ years and have accumulated lots of specialized tools, too much to try to list here. But I wanted to share these two. I've owned these two for at least 30 years. I've used both of these tools on this job more than any other job I've done. It was the only way to get some of the screws back in place.




All the Best on this Harris. Keep coming back if you need more.

Acta

 

Two things the bit size is T30 not a T27. Second to remove the coils you do not need wd40. Grab the end of the coil towards front of car and pull reasonably hard for about 30 seconds. Then pull coil at opposite end for about 30 seconds. Doing this repeatedly will slowly but release the coil.

PS the panel that surrounds the battery has two bolts you can remove and this will loosen the panel. You do not need to remove it. It will move a bit and give more space to access the breather tube on passenger side. Also helps to use 1/4 inch drive tools.

 

Changing the plugs sounds awfully complicated. How competent are most Mercedes dealerships at doing this?

 

Hard to say. It depends on how many of these cars they see in the back room and then how many of the techs get to work on them. Some shops will use a dedicated AMG tech, while other shops want all their techs to be able to service all models. That makes for a lot of learning on the job.

I'm positive the "overfilling" of oil on the dry sump platform comes BC the tech doesn't know how to do it according to the factory process (and they think it's just another engine with oil in it) or they know how hard it is and they intentionally "short" the process.

 

I got a torque wrench that I use on my Harley repairs, which is 1/4 drive and in inch lbs. So for 11.6 ft /bs , I will torque the plugs down to 139-140 inch/lbs.

 

I got the coils out from the passenger side too, but three out of the ignition coil boots got stuck in their holes! So, I proceeded to buy long nose pliers, and they eventually came out. Mercedes should had installed thinner wall boots, or they should had made the plug holes wider. Other than tinkering with cars and Harley for years I am a mechanical engineer with 37 years in the business and understand quality control and many other aspects of engineering design and having owned Mercedes in the past, so I am surprised for the sightedness on their behalf...

 

Hi Harris,

SO....You're now a veteran! Good...another knowledgeable member on changing plugs! You can take the next inquiry now and share your expertise! Out of curiosity, would you be willing to share the year and mileage? Have you tracked the car?

Reason for the questions - given the struggle you had with the SP boots, there might be a correlation with heat cycles and based on a combination of time, and use, we might be able to forewarn future "adventurists" who would dare to plow head first into this "Dark Place".

BTW, I am Mechanical Engineer as well. Without giving up the years on the job, (you'll probably guess) and since you're from Boston, my first Engineering position out of school was working for Ken Olson. I spent a fair amount of my career around Boston and the Maynard area. I helped start the manufacturing plants in Albuquerque and Phoenix and did a goodly share of consulting with the Roxbury plant too. I very much enjoyed Boston...especially the North End.

 

mileage: 34K. if you want to find a little bit about me you can look me up in LinkedIn...if you send me an email I can email you my last name, so you can look me up...

 

"Regarding the breather tube on the passenger's side, there are 5 screws that hold it in place, not just the 3. They are marked item 15 in this pic"

To get the passenger tube removed do you have to remo0ve any of the metal tubing that is is front of the back end part of the black tuibng? Or can you just slide it out without removing any of the metal tubing?

 

You need to remove the EVAC tubes to get the plugs out. I was told that there are gaskets on the EVAC tubes that need to be replaced. Anyone know if that is true?rue?

 

I did not replace any gaskets but prolly would if I had known about them.

PS very important about the tubes you’re talking about that is not explained in WIS. After all the bolts are removed the tubes slides straight back (towards back of car) to remove them. If they do not slide straight back then you missed the front bolt.