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Pelican Technical Article:

Spark Plug Replacement

Time:

1 hour1 hr

Tab:

$20

Talent:

**

Tools:

Torque wrench, spark plug socket, screwdrivers, swivel head 8mm socket, 10mm wrench, spark plug gauge

Applicable Models:

Mercedes-Benz E320 (1996-97)

Parts Required:

New Spark Plugs

Hot Tip:

Replace plugs with the engine cold.

Performance Gain:

Smoother running engine, better MPG

Complementary Modification:

Replace coil packs if needed

One basic tune-up procedure for just about any car on the road is the replacement of your spark plugs and spark plug wires. I recommend examining your spark plugs every 30,000 miles and as the car ages, it'd be a good idea to check them more frequently. If you see signs of burnt electrodes, oil, etc., replace them. In reality, you can probably go longer than that, (most manufacturers recommend an interval of 100,000 miles) but, you never really quite know how long the plugs are going to last. A lot of factors can contribute to the plugs wearing out faster than you might expect.

On the M104 engine, Mercedes has eliminated the use of a distributor by integrating a "wasted spark" ignition setup with three coils. In a wasted spark system, the spark plugs fire in pairs even though one plug is on the compression stroke and the other plug is on its exhaust stroke. The extra spark on the exhaust stroke has no effect and is considered to be "wasted." The main advantage of using this setup is that there are half as many components needed for the engine and thus less expensive to produce.

Begin by prepping the car. The only thing that you really need to do is to 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. Now remove the upper airbox cover to the left of the engine. This is held in place by a series of clips on the outside of the cover. Once the upper cover is removed, release the two clips holding the cover to the MAF sensor tube. Next remove the hose clamp holding the MAF sensor tube to the plenum and squeeze the two clips holding the electrical connector to the MAF sensor. Simply pull the connector off, then pull the sensor tube out of the plenum.

Now remove the three 10mm bolts holding the upper intake hose to the valve cover. You'll also need to loosen the hose clamp holding the upper intake plenum to the throttle body. The clamp itself is located in a tight space. A set of universal joint sockets, as shown here, makes this job much easier. Once the hose clamp is loose, pull the whole intake plenum assembly up and off the valve cover. Now remove the 5mm hex bolts securing the valve cover insert piece to the valve cover. Also take note of the firing order of the car embossed into the insert piece. This diagram is helpful if you forget where each sparkplug lead goes on the car. Once the insert piece is removed, you'll see the ignition coils and wires underneath.

Now remove each spark plug coil and connector by pulling it straight up. The spark plug itself is directly below. Use a spark plug socket here. You'll need a long extension on the end of your ratchet in order to remove the old plugs. Slide the extension all the way down until you feel the socket firmly grip the spark plug. The spark plugs should be tight in the cylinder head, but not overly difficult to remove with a little force. 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 âsee' what is going on inside your combustion chamber. Typically, you want to see a slightly tan, burnt appearance. This will indicate that your engine is running normally.

Before you install your new plugs, it's a good idea to check the gap between the the metal of the center electrode, and the L-shaped metal bar that hangs over it. This is called gapping. For W210 (and W124) the recommended gap is .32 or 0.8mm. A spark plug gauge is needed to accomplish this task. If the plugs meet this specification, you can begin to install each new plug into the cylinder heads without using any anti-seize compound. Torque the spark plugs to 27 Nm (20 ft-lbs). It's worth noting that failure to torque the spark plugs to the correct setting can result in the spark plugs slowly backing themselves out until they eventually blow completely out of the head. This can also damage the threads.

If you are replacing the coils as well, simply pull the electrical connection off each and install the new coil in place of the old one.

One high-performance automotive manufacturer, Porsche, doesn't recommend using anti-seize compound on spark plugs for any of their engines. 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. Keeping those findings in mind, I make the same recommendations for the M104, don't use anti-seize compound on the spark plugs.

New spark plugs and wires are an essential part of any tune up.
Figure 1

New spark plugs and wires are an essential part of any tune up. It's a good idea to inspect your plugs and wires every 30,000 miles. If the wires appear cracked or frayed, replace them.

Begin by removing the upper airbox cover.
Figure 2

Begin by removing the upper airbox cover. This is held in place by a series of clips on the outside of the cover. Once the upper cover is removed, release the two clips holding the cover to the MAF sensor tube. Please refer to our article on replacing your air filter for more information.

Next remove the hose clamp holding the MAF sensor tube to the plenum (green arrow) and squeeze the two clips (purple arrows) holding the electrical connector to the MAF sensor.
Figure 3

Next remove the hose clamp holding the MAF sensor tube to the plenum (green arrow) and squeeze the two clips (purple arrows) holding the electrical connector to the MAF sensor. Simply pull the connector off then pull the sensor tube out of the plenum.

Now remove the three 10mm bolts holding the upper intake hose to the valve cover (green arrows).
Figure 4

Now remove the three 10mm bolts holding the upper intake hose to the valve cover (green arrows).

You'll also need to loosen the hose clamp holding the upper intake plenum to the throttle body.
Figure 5

You'll also need to loosen the hose clamp holding the upper intake plenum to the throttle body. The clamp itself is located in a tight space. A set of universal joint sockets as shown here makes this job much easier. Once the hose clamp is loose, pull the whole intake plenum assembly up and off the valve cover.

Now remove the 5mm hex bolts securing the valve cover insert piece to the valve cover (green arrows).
Figure 6

Now remove the 5mm hex bolts securing the valve cover insert piece to the valve cover (green arrows). Also take note of the firing order of the car embossed into the insert piece (red arrow). This diagram is helpful if you forget where each sparkplug lead goes on the car.

Once the insert piece is removed, you'll see the ignition coils and wires underneath.
Figure 7

Once the insert piece is removed, you'll see the ignition coils and wires underneath.

The E320 uses what is called a wasted spark ignition setup.
Figure 8

The E320 uses what is called a wasted spark ignition setup. This means that each ignition coil ignites two cylinders 180 degrees out from each other and uses one coil to power two cylinders. What this means is that you'll see three coil packs with three branched wires coming off them going to each spark plug. In this picture you see the branched ignition connector coming from the coil. Pull it up to release it from the spark plug.

In thisPicture we see the coil itself on top of one of the spark plugs.
Figure 9

In this picture we see the coil itself on top of one of the spark plugs. Simply pull it up to lift it up and off the spark plug.

You'll need a long extension on the end of your ratchet in order to remove the old plugs.
Figure 10

You'll need a long extension on the end of your ratchet in order to remove the old plugs. Slide the extension all the way down until you feel the socket firmly grip the spark plug. The spark plugs should be tight in the cylinder head, but not overly difficult to remove with a little force.

Take the new spark plug and push it into the specialized spark plug socket.
Figure 11

Take the new spark plug and push it into the specialized spark plug socket. There is a small rubber retainer ring inside that will firmly grip the plug and prevent you from dropping it inside the cylinder head. Carefully thread the new spark plug into the cylinder head by hand. Once seated in the head, use a torque wrench to torque the plugs to 27Nm (20 ft/lbs.).

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Comments and Suggestions:
rob4mm Comments: In fig 5, a swivel socket is not needed if you have a long screwdriver to go under the intake and reach the screw on the hose clamp.
July 17, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
bobby Comments: my e320 is a 1998. getting ready to change plugs & wires.your tech. article stops at 1997. can you give me any info. before I start?
February 22, 2016
  Followup from the Pelican Staff: We don't currently have that tech article. If we get a chance to perform the procedure, we will be sure to document it.

I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
IbbenZin Comments: You've left out the important part "gapping" which in my understanding is .32 or 0.8mm otherwise new spark plugs aren't going to do a good job despite the "new" w124 and w210 have the same engine same gap for both
February 1, 2016
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it. I will have the article updated.
- Nick at Pelican Parts
 
Molly Comments: Hi I have a c230 sport we changed all spark plugs but I'm still getting a mis firer on bank two and my check engen light is still on and has power just not like it did . And it got a slight shake when you stop at light now . Sense we done it . Please help
November 10, 2015
  Followup from the Pelican Staff: I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
Broken Heart Comments: Hi everyone I would like to know the cylinder firing order on w 21... Specifically I have e 55 amg 2001 what I mean is cylinder one starts from first one on my left hand when I open the car hood and where the second cylinder would be... Thanks a lot Nick.
May 14, 2015
  Followup from the Pelican Staff: Cyl 1 on the right side, followed by. That is for the 113 engine, which you should have. See attached. - Nick at Pelican Parts
Tommy 229 Comments: I have a problem when removing the coil pack the rubber insulator is jammed onto the plug. Tried removing with pliers molegrips etc but stuck fast. Any suggestions would be good. My car is 97 Mercedes E200 W210 engine.
Kind Regards,
Paul.
May 3, 2015
  Followup from the Pelican Staff: It is probably melted on. You will need to replace it once you get it off. Try using pliers to pull it off. If it won't budge, try to tear it using a flathead screwdriver. - Nick at Pelican Parts  
Broken Heart Comments: Hi everyone, I just want to confirm something... When they refer to any part in engine.. Say cylinder and they say bank one or left bank... So how do I know which side they refer to... When I am facing my front car or when I'm in my car should refer to left or right bank of engine. Thanks
April 24, 2015
  Followup from the Pelican Staff: bank 1 is always where cylinder 1 is. Bank two would the opposite side. - Nick at Pelican Parts  
jojo Comments: Hi nick thank you for responding
I changed coil packs as i thought this could be the problem as the car had no power,no engine light is on.
I will check the compression, as i did put in 12 new spark plugs, the one bank seems completely fine, just one side seems to be completely dead.
Thanks again
April 7, 2015
  Followup from the Pelican Staff: If one bank is dead, look at something that would cause the whole bank to go out. Fuel pressure, electrical, major vacuum leak, etc. - Nick at Pelican Parts  
jojo Comments: Hello
I just replaced the 2 coil pack on my Mercedes c280.
Now it seems like 1 entire bank is dead, i replaced this 2 weeks ago. The car has absolutely no power at all,please advise what could be the reason of this. Many thanks
April 7, 2015
  Followup from the Pelican Staff: Why did you replace the coil in the first place? Is the check engine light on? Could be an engine misfire. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
Geoff Comments: Hi,

I have a 2000 W210 E320 and would like to know if the steps are still the same? I know that the models are closely related.
November 23, 2014
  Followup from the Pelican Staff: No. This tech article applies to:
W210 E320 (1996-97) - Nick at Pelican Parts
 
anna Comments: i have a 2001 320 benz and i would like to know if i need to change my transmission fuel
November 12, 2014
  Followup from the Pelican Staff: Transmission fluid? You should check if it is dirty or have a shop check it out for you. - Nick at Pelican Parts  
LOH Comments: Hi, my W124 230E engine is having misfiring problem when raining. When happen the rpm will not reach 2500 even the acceleration pedal is fully press. When rain stop, the engine will run smoothly. Hope can get some advice. Thanks.
September 12, 2014
  Followup from the Pelican Staff: Sounds like you have an ignition system voltage leak. I would check spark, fuel and compression on all cylinders, to be safe. - Nick at Pelican Parts  
Simon Comments: Thanks for the tutorial. My s320 starts great, runs well for a few miles then it has a rough idle and hesitation at stops. The has codes that state misfire on 3 and 4. I just ordered a MAF from you, is there any way to tell if it may be the coil banks causing this...would they go bad after the car has warmed up? Thanks!
August 28, 2014
  Followup from the Pelican Staff: You can test spark at each coil using an HEI spark tester. To be safe, I would check spark, fuel and compression on all cylinders. - Nick at Pelican Parts  
theo Comments: very black spark plus
August 19, 2014
  Followup from the Pelican Staff: Could be high fuel pressure. I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
 
Rudz Comments: Dear Staff,

thank for your input,

I checked the MAF, it is working within range,
But I am noticing something when start up an driving for 20 min the temperature does not reach 80 degree or reach it but very slowly, should I change the spark plug,
thanks & Regards
July 6, 2014
  Followup from the Pelican Staff: If the engine is not reaching operating temp, there could be an issue with the thermostat. I would start there. - Nick at Pelican Parts  
Rudz Comments: Hi,

Thank you for your help:
I have changed the breather hose part number - 271 018 14 82 &
271 018 12 82 + the small valve it was broken related to it,

I wanted to ask you, I had the same issue persisting,
I changed the Gas station and the problem is solved, the car after 10 min of stopping does not stumble,

BUT the car engine light went off and came on again indicating RICH MIXTURE,
Can it be the spark plugs,Oxygen sensor...

regards,
July 2, 2014
  Followup from the Pelican Staff: Could be a faulty MAF sensor. I would check fuel trim and see how and when it is skewed. - Nick at Pelican Parts  
Rudz Comments: Hi,
I have a C230 2005, Whenever being warm and stopped for 10 min then restarted a hestitation and stumbling is sensed then about 30 sec and the engine runs normally,
The engine is giving error 201C/ P0172.
Thanks & regards
July 1, 2014
  Followup from the Pelican Staff: You could have a vacuum leak or a fuel trim fault. I would check fuel trim using a Mercedes-benz scan tool. You will be able to check when it is skewed and in what direction, rich or lean. - Nick at Pelican Parts  
hrg207 Comments: Hi, the coilpack pulls out without removing the grubscrew, which is good to know. Thanks for your help.
Regards.
June 4, 2014
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
 
hrg207 Comments: Hi, here's the picture of the coil pack as you requested. The grubscrew sits in the brass colour hole, bottom right corner. Regards.
June 2, 2014
  Followup from the Pelican Staff: I do not think that fastener has to come out. Is the coil stuck otherwise? - Nick at Pelican Parts  
hrg207 Comments: Excellent article. On my 96 E320 Coupe there is a small grub screw in the corner of each coil pack. The heads on two of these have been damaged making them difficult to remove. Is it necessary to unscrew them to remove the coil pack? Thanks.
May 26, 2014
  Followup from the Pelican Staff: Can you share a photo of the coil? - Nick at Pelican Parts  
Dralloc Comments: Awesome instructions and great pics to go with the instructions. On the change out of my 97 E320 104 I-6 spark plugs, I didn't see any info on what the gaps need to be for the 104 I-6 engine spark plugs?
May 18, 2014
  Followup from the Pelican Staff: If it is a platinum or dual-electrode plug, there is no gap to adjust. Is single electrode, check the emission label under the engine hood. Plug gap should be listed. - Nick at Pelican Parts  
Des Des Comments: Im thinking of replacing my beautiful W124 230E 1994 prefacelift which runs sweet and its a manual,with a W210 E320 M104 i6 engine late 1997,do u think its a great idea,the 230E is nice but ive noticed the fuel consumption of the 2,seems its almost the same.?
May 17, 2014
  Followup from the Pelican Staff: The new models are quite nice. I'd go for it if it is a nice vehicle. - Nick at Pelican Parts  
Mat Cendana Comments: The coil packs: how long do they last and when should I replace them? My car has two coils E200, 4 cylinders - when replacing, should it be both at the same time or is it okay to just replace one?
April 8, 2014
  Followup from the Pelican Staff: You only replace them when they are faulty. It is a good idea to replace them in sets, as if one failed, the other cannot be far behind. - Nick at Pelican Parts  
Robin Comments: HI THERE, CAN YOU TELL ME WHAT IS THE SPARK PLUG TORQUE SETTINGS FOR THE FOLLOWING MODELS:
W110 230/6, W115230/4, W121190B Ponton. Thank you and kind regards.
February 22, 2014
  Followup from the Pelican Staff: Sorry, I don't have that information. - Nick at Pelican Parts  
Richard Comments: I have a 1991 300CE which NGK spark plug is best ? Is this a protuded tip ?. Thanks Richard
December 12, 2013
  Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
zoli Comments: I really like pelicanparts DIY tutorials, THANKS!

My question, I have a M111.957 engine w210 2.0 compressor, 2001. This is inline 4 cyl engine.

Is the process much different to this tutorial?

Thanks
December 3, 2013
  Followup from the Pelican Staff: I'm not sure what "process" you're referring to. It's always best to find the specific manual for your model. - Nick at Pelican Parts  
papazak Comments: I have a 1999e320 it shakes when stopped at the trafick light or about to take off, theres a small hesitation, could this be my spark plugs?
November 8, 2013
  Followup from the Pelican Staff: Yes but it could be many other things. If you can unplug each injector one at a time. Each time you unplug an injector the engine rpm should drop. If you unplug an injector and the rpm does not drop then that cylinder is not contributing any power. Check the spark plug and compression on that cylinder. - Kerry at Pelican Parts  
Wallace Comments: I have a 1994 E320 with 145,000 miles on it. It runs great....until it rains or I drive through a puddle of water. Then it starts shaking, has smoke coming from tail pipe and runs rough. And when this happens, it drinks the gas like nothing. I had half a tank and drove home 20 miles after leaving the gas station and when i got home the light was back on for low fuel. Any suggestions
November 5, 2013
  Followup from the Pelican Staff: Usuaaly as a rule with mechanics when moisture is around and the car runs poor the problem is in you ignition system. Use a spray water bottle with salt or soapy solution and spray down your distributor cap or coils and spark plug wires. If you see arcing or the car runs poor give yourself a full tune up replacing all of the ignition components - Kerry at Pelican Parts  
Jared Comments: Hello, I have a 95 S320 and when I went to pull the ignition coils off they didn't come all the way out, they seperated at the start of the tubing. In cylinder #6 the ignition coil was much harder to pull out and it seperated close to the bottom of the coil where. Any suggestions on how to proceed? Should I order some new coils to go along with the plugs? I don't know much about the coils or if I damaged them or not. I can upload pictures if it will help... Any helpful responses are MUCH appreciated.

October 6, 2013
  Followup from the Pelican Staff: Please share some photos of the damaged coil. Are you able to remove the boots from the spark plugs by twisting them while pulling up? - Nick at Pelican Parts  
sherry Comments: Sir , i have Mercedes benz c class kompressor it,s some kind of a problem . actually it start Normally but After 1 or 2 minutes it start shaking for a 3 to 5 second and then Engine top running what is the problem how could it b repair what is the cause sir please help me i m waitng... thank you
September 29, 2013
  Followup from the Pelican Staff: When the car shuts off can you restart it? Are you losing fuel pressure, injector pulse or spark? You are going to have to test for these three things and see what the car is missing. - Kerry at Pelican Parts  
Sherry Comments: U r doing Great Job So nice of You Thanks 4 all this ...:
September 29, 2013
  Followup from the Pelican Staff: Thanks for the kudos - Kerry at Pelican Parts  
mikegoldy Comments: Second time I have used your site for my 1995 Mercedes SL320. Thank you for the great instructions.
August 31, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help. - Nick at Pelican Parts  
majid3 Comments: Any info, or pictures preferabley, on changing air filter and spark plugs on 1999 W210 E55.
Also locating, removing/cleaning the Idle Control Valve would also be most appreciated. Many Thanks
August 15, 2013
  Followup from the Pelican Staff: Hi, we have some of the info you requested here: http://www.pelicanparts.com/techarticles/Mercedes-Benz/MBZ_Tech_Index_old.htm

The only article I don't think we have is the idle valve. if we get the chance, we will do the work and document it. - Nick at Pelican Parts
 
george Comments: very good site wonderfull give an A-
need picture on mercedes s320 front door panel and regulator removel
October 3, 2012
  Followup from the Pelican Staff: Sorry we don't have this picture at the moment. roy@pelicanparts  

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