#4 Glow Plug Removal
Thread Starter
Super Member
Joined: Jan 2010
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From: The Villages, Florida
2006 E320 CDI
#4 Glow Plug Removal
I am starting to get frustrated! I only have one glow plug to change. They have approximately 25k miles since the last time all six were replaced. I have the glow plug turning freely in the cylinder but I cannot pull it out. Could carbon be holding it in? I tightened in back into the cylinder and loosened it again to make sure it just was not spinning. Any assistance is appreciated!
2006 e320 cdi
Mike T.
2006 e320 cdi
Mike T.
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Joined: Jan 2010
Posts: 301
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1997 E300D
If I understand you correctly, the plug will back out until the threads clear the head and it just spins, but you can not pull it the rest of the way out. If this is correct, the end of the plug is either enlarged or caught on carbon build up around the tip. Since you have screwed it back in, can you run the engine up to working temperature and see if it will come out with the head hot. Once the threads are out of the head, I would think that you should be able to rig up something to pull the plug straight out, but I have no experience with your engine. Be sure to ream out the carbon before putting the new plug back in. I am curious as to the brand of plug you are trying to remove. I have heard of a brand that had the tips spread out when they failed. I hear the best brand is Beru or Bosch.
Thread Starter
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Joined: Jan 2010
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From: The Villages, Florida
2006 E320 CDI
I am not sure if the threads have completely cleared the head. I finally put everything back together and will think about this a while. The plug brand is Beru. With my luck I probably made matters much worst instead of just bringing it to my indie. I just thought that it would be a simple ten minute job!
Mike T.
Mike T.
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Joined: Jun 2008
Posts: 835
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From: Bay Area, CA
09' E320
The first thing to do is to confirm if the threads are fully disengaged or not.
Carbon buildup can lock a GP in the head which is why is it so important to ream the hole before installing a new GP.
Search youtube for OM648 Glow plug removal; Klann(?) makes a tool set for drilling and pulling and that video ought to give you ideas to remove yours.
Carbon buildup can lock a GP in the head which is why is it so important to ream the hole before installing a new GP.
Search youtube for OM648 Glow plug removal; Klann(?) makes a tool set for drilling and pulling and that video ought to give you ideas to remove yours.
Thread Starter
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Joined: Jan 2010
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From: The Villages, Florida
2006 E320 CDI
Thanks T, I will check out the video. I might just wait until the week after next and let my indie mess with it. I just thought that it would be a ten minute job. With only 22k on this set of glow plugs, I am thinking that the tip may have ballooned some in which I got from am reading some other peoples stories. Also come to think of it, I do not believe that my last indie cleaned or reamed the threads prior to installing the new glow plugs. Lesson learned the hard way!
Mike T.
Mike T.
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Joined: Mar 2009
Posts: 430
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From: USA, EU
06 E320 CDI (GONE), 14 Jeep GC EcoDiesel, 01 Disco II (GONE), 09 BMW X3 3.0 Si Xdrive
Combustion gases cannot pass above the tip of the glow plug, thus making it impossible for carbon to build up around the threads. Also is impossible to have carbon build up on the tip due to high temperature when the glow plug is working (cold carbon when heated will crack and fail off) unless you drove the car for long time after the plug burned out. I just replace one off mine, it was #4 also and did not use anti seize paste, apparently Dealership did not use any first time when they changed all of them under warranty, as you can see from the picture.
When you unscrew it does it move up and down as you pull or not, if does not move probably is still screwed so keep turning it. Threads are about 10 mm long so when you are unscrewing it out it will clear the tip and will scrape any carbon.
When you unscrew it does it move up and down as you pull or not, if does not move probably is still screwed so keep turning it. Threads are about 10 mm long so when you are unscrewing it out it will clear the tip and will scrape any carbon.
Thread Starter
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Joined: Jan 2010
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From: The Villages, Florida
2006 E320 CDI
I screwed the heck out of it. The threads must have cleared the head. I tried pulling on it (many times) with a pair of long nose pliers but I cannot get a good grip on it. I figure that a mini "dent puller" device will do the trick if I can get something small enough to fit under the nut on the glow plug. Since this is my main vehicle for transportation, I will just take it to my indie next week and let him mess with it. The glow plug only has 22k on it so no carbon should be holding it in. The only thing I can think of is that the threads were not reamed when they were installed.
Mike T.
Mike T.
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From: USA, EU
06 E320 CDI (GONE), 14 Jeep GC EcoDiesel, 01 Disco II (GONE), 09 BMW X3 3.0 Si Xdrive
If it is not been reamed they should be seized and will not be able to turn it, thus you applied to much torque and now is broken and is turning around the wire inside of it if is turning freely.
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Joined: Jun 2008
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From: Bay Area, CA
09' E320
I screwed the heck out of it. The threads must have cleared the head. I tried pulling on it (many times) with a pair of long nose pliers but I cannot get a good grip on it. I figure that a mini "dent puller" device will do the trick if I can get something small enough to fit under the nut on the glow plug. Since this is my main vehicle for transportation, I will just take it to my indie next week and let him mess with it. The glow plug only has 22k on it so no carbon should be holding it in. The only thing I can think of is that the threads were not reamed when they were installed.
Mike T.
Mike T.
If it snapped and is all the way out, you need to cut off the electrode and drill the remaining internal electrode out and tap the body of the GP and then use a homemade puller (oversized socket, washers, threaded rod and nuts) to pull it out. If its still threaded, you have to first drill the GP out from the treaded area.
The video shows the principles.
Its not the end of the world.
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2008 R320 CDI, 2006 smart fortwo cabrio, 1983 240D, 1982 300SD, 1980 300SD
Sounds like the glow plug is broken, they snap off below the threads and leave the long body part in the cylinder, the only thing holding it together are the internals (wire etc), same thing happens on Ford spark plugs the threads come loose but not the body of the plug. They sell removal kits for such problems, but they are not necessarily great tools or the answer to all problems each removal is different and some tool don't grab well enough to remove them.
These glow plugs stick at the end of the bore way down where the tip enters the cylinder and the carbon creeps up the bore, it is not around the heater element but above that. They can also corrode in place dissimilar metals between the glow plug and cylinder head but this takes years to happen.
I coat the entire body with antiseize, there are all kinds of different types to help prevent these problems, research is key.
These glow plugs stick at the end of the bore way down where the tip enters the cylinder and the carbon creeps up the bore, it is not around the heater element but above that. They can also corrode in place dissimilar metals between the glow plug and cylinder head but this takes years to happen.
I coat the entire body with antiseize, there are all kinds of different types to help prevent these problems, research is key.
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Joined: Apr 2010
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05 MB E320 CDI
I had a similar problem when removing #5. The threads came undone but it still wouldn't come out just kept spinning. You need something to pull on the plug and keep turning it too. This is what I used:
It's like a long pliers with a circle on the end so just grab the plug and keep the socket on so you can turn and pull. I spayed wd40 aswell to just loosen up all the carbon. The glow plug was covered in carbon from the threads downward so I believe that's what made it hard to come out.
Next question is it a bad thing that carbon is getting up there like it's suppose to be sealed.
It's like a long pliers with a circle on the end so just grab the plug and keep the socket on so you can turn and pull. I spayed wd40 aswell to just loosen up all the carbon. The glow plug was covered in carbon from the threads downward so I believe that's what made it hard to come out.
Next question is it a bad thing that carbon is getting up there like it's suppose to be sealed.
Thread Starter
Super Member
Joined: Jan 2010
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From: The Villages, Florida
2006 E320 CDI
I dropped my car off to my indie Sunday night. At approximately 4pm on Monday, the shop called me and told me the car was ready. When I picked it up I spoke to the mechanic that worked on it. He said that it took him a couple of hours to get the plug out. It did come out in one piece. He said that it looked like an original glow plug in which I told him that I saw my Northern VA indie change them out 20k miles ago. Anyway, $135 later and all is fixed.
Also, it was a good thing that I provided the Beru glow plug. I told the mechanic that the 05/06 cdi's use the 5v glow plug, he was not aware of this. I am sure he would have installed a 12v Bosch glow plug if he ordered the part.
Mike T.
Also, it was a good thing that I provided the Beru glow plug. I told the mechanic that the 05/06 cdi's use the 5v glow plug, he was not aware of this. I am sure he would have installed a 12v Bosch glow plug if he ordered the part.
Mike T.
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Joined: Sep 2009
Posts: 40
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1971 280 SL
Outstanding instructions! I just changed my #1, 2, & 3 Beru plugs in about 45 minutes. Trickiest part was removing the cap off each. After examining them closely I noticed 4 holes lined across the bottom plug wall outside. After digging in my toolbox I came across an old pry tool that looked like an ice pick with a sharp 90 degree bend at the very end. It fit perfectly in the cap holes and with a little patience I was able to pop them all off.
BTW, not appreciable carbon buildup or trouble removing them, thankfully. These three have been out since last winter.
What a great forum with great folks, thanks!
Roadstir -VA
BTW, not appreciable carbon buildup or trouble removing them, thankfully. These three have been out since last winter.
What a great forum with great folks, thanks!
Roadstir -VA
