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Glow plug removal, '06 CDI

11K views 20 replies 7 participants last post by  A1Sailor 
#1 ·
Got a new set of glow plugs today & decided to go ahead and see what can go wrong. Five of six came right out with no issue, but #5 was a booger from the get go. It fought me all the way but I finally got it clear of the threaded portion and about 1/4" beyond, but there it stays. Needle nose vice grips don't give me sufficient purchase or a fulcrum from which to work. I'd be more than happy to try brute force if I could just see a way to get any purchase. I've sprayed penetrant liberally. I've tried chucking up the socket in a drill motor and spinning it while pulling lightly. No joy there at all. Tweezing a bit with the long needle nose pliers just now I'm seeing that the threaded portion & hex will spin freely but the top connector is stuck tight; they've become separated. I'm at the point that I'm thinking of putting the other 5 new plugs in, throwing some weighted padding on top of the engine and starting it up to see if compression will push it out. Is that one of the worst Ideas I've ever had? If so, what better?
 
#2 ·
we have used the compression technique before. it works. we lay several fender cloths over the eng and rev it to about 2000 rpms. they usually shoot out.

also get that eng hot as you can and see if you can pull it out. I spent 6 hours one day getting a plug out of cyl 4. took my time to not damage the head. this plug was bent reasoning for not coming out correctly.
 
#3 · (Edited)
Thank God you got it past the threads and it didn't seize up on you. It would be nice to have a miniature slide hammer setup to get it out. I wonder if the rounded electrical connector on top could be threaded with a die and then attach an elongated all thread coupling hex nut with some all thread. You could make a slide hammer setup with that. Edit: I just ran out to the garage to look at one of my old glow plugs to get a die size for the stud and remembered that the glowplugs are somewhat recessed, and using a die to thread the stud may be impossible :( I would be tempted to use the engine running method and see if the engine heat helps it out first though.
 
#4 ·
Yep, I thought of a die and threading the top but there's just not room enough. I spent several hours on it today. Took it for a long freeway run to see if compression would pop it out; no such luck. Nothing else worked either. Someone on another forum provided me an ebay link to this tool:

CDI Glow Plug Tool | KTC Auto Tools

It's not clear how/if it works but at the price I decided to give it a whirl. If they ship tomorrow I should have it before xmas. Meanwhile I'm going to resume trying to pretend I have a life for the next few days.
 
#5 · (Edited)
That is an interesting tool there. It is quite cheap for sure. I don't believe that will work for glow plugs where the threads break off. I guess that would work fine for swollen glowplugs and ones(like it mentions) that are carbon bound. Looks like it must slip over the lip underneath the 4mm round stud and locks in. It must allow you to jack out the GP from there.

Here is another option with the reamers to clear the carbon:

http://www.ebay.com/itm/3PC-GLOW-PL...033738?hash=item3ab8c52fca:g:BdEAAOSwjVVVvegy

You would want to verify that it will work with the OM648. I am thinking it will work since out OM648 uses a 10mm thread on the glow plug, but do due diligence and confirm it with the seller first.
 
#6 ·
I'm hoping you're right about function. I'll just have to test their returns policy if it really looks like it won't work. That link you supplied is interesting also but for one thing I'd rather not wait for shipping from across the Pond, and for another I'm wondering if 6mm is the right diameter for the reamer. When I had the other plugs out I found that I could just slip a 3/16" hardwood dowel through the bore hole with very light to no interference. It didn't look as though there was any carbon build-up in the others and as 3/16" translates to less than 5mm I'm a bit suspicious.
 
#9 ·
Well, the verdict is in. Tool arrived via priority mail this morning. In order to get adequate access to insert it I had to bend a cheap 8mm box end wrench so that I could remove the lower bolt securing the lifting eye - which also helps support the fuel rail - that's right next to #5 cyl. The offset wrench set that also arrived today had too great an offset to clear the fuel rail. With that bolt removed - I'd removed the lower bolt a few days ago - I tapped the eye back a bit and had adequate clearance to insert the tool after also trimming a projecting bit off the plastic cable housing. The knurled end turns out to be a spring loaded retracting cylinder that houses a couple of hardened steel pins that grip the shell of the plug on the shoulder that's immediately below the hex. I spun the threaded end out until all the slack was out, inserted the ratchet and continued to turn. The good news is that the tool worked perfectly. The bad is that the shell had sheared immediately below the threaded portion so that all that came out was the connector and the upper part of the shell. If I'd stopped the other day as soon as the threaded portion cleared and looked for the correct tool then, or maybe if I'd been more patient with the penetrant, I might not be in the pickle that I find myself in now.

About the tool, it appears to be very well made for the $$ and more than adequate to its purpose with one little caveat pertaining to the OM648 engine. The bloody plastic cable housing is pretty seriously in the way of access to #4 cyl, maybe somewhat less so for #6 cyl, and it might be a bit of a squeeze to get it onto #1 due to all the cables that exit the housing immediately above. It might be necessary to trim a little projecting tab above #3 , but with a warm engine that's easily done with a utility knife. All in all though I'd say it's a tool worth having if you contemplate ever needing to remove cdi glow plugs. I bought mine directly from KTC; it was about a buck less from them than ebay including shipping and they specified shipping by priority mail. What more can I say? I ordered Sunday evening and have the tool in hand today.

So, I guess it's time for me to throw in the towel and look for a pro who has the equipment and expertise to drill the thing out. The entire electrode is projecting and the sheared off lower part of the shell is projecting about 1/4" above the threaded hole in the head. Electrode appears to be a press fit onto the connector. Anybody got a recommendation for a good mechanic in the SF Bay Area, preferably close to the north Peninsula? Failing that, what questions should I be asking in an attempt to determine competence?
 
#10 ·
SBJoe, thank you for the review and sorry for the outcome. Have you seen the following video on youtube? https://youtu.be/e89v7eib0as

It's for a Glow Plug Removal Tool with Thread repair kit Mercedes CDI (KL-0369-30 K). Looks pretty impressive in the video however it's also expensive but depending upon the labor to remove you may be able to justify it.

Please keep us updated on your progress to get this solved as I am sure others will be following in your steps sooner or later.
 
#11 ·
Yes, I had seen that video recently. Thanks though, as it was interesting to see it again from a somewhat different perspective. I've been reviewing the WIS though and found a Mercedes tool kit, 611 589 01 99 00, for removal of plugs when thread repair isn't required. It's a bit pricey at something on the order of $900 shipped. Further searching reveals that Baum makes a similar kit, B900-0199:
Glow Plug Removal Set | Baum Tools | B900-0199
Interestingly, I've not found any mention of the use of reamers anywhere in the procedure for g/p removal. Instead, it specifies the use of pipe brushes 9mm & 5.3mm in diameter; these brushes are included in the Mercedes kit but not in any of the aftermkt kits I've run across. Prices vary pretty radically on these kits. Here's one with a video of the kit being used:
Win Tools W900-0199 Broken Glow Plug Removal Tool - Wise Auto Tools
And another real cheapie from fleabay:
8mm 10mm Glow Plug Removal Remover Damage Extractor 16 PC Tool Kit | eBay
The other main advantage of the factory kit is that it includes an alignment sleeve to insure accuracy when drilling/tapping the shell for removal. I guess you pays your money and you takes your chances. Decisions, decisions...
 
#13 ·
Thx, I was inclining toward it anyway as Baum is pretty much a known quantity; the others not so much. Looks like a pretty reasonable price point as well for what it is. I've got one cylindrical wire brush that is of a size to work pretty well on the side bore of the deep well. Cleaning around the seating area and into the small bore at the bottom is still unresolved though.
 
#14 ·
Solution perhaps

I have done lots of these , you can get a cheap kit off ebayn, but they are cheap,for a reason, drill out the core with the guide,then drill out the thread approx 20 mm, then tap the glow plug lower part at this point the plug normally comes out, if it doesn't then use the puller,
The lower part normally comes out on these unlike the v6
eBay 291643378483. Watch the drill bits they do break
 
#15 ·
I have stuck glow plug #5 cyl, the threaded portion looks fully out of head, the plug just turns, have soaked it overnight with PB Blaster and it turns easier now but will not come out. Does not seem broken at this point.

Is it ok to cover the glow plug and start motor and let it warm up- how long should motor run for?

Would be nice if a slide tool existed that would fit under hex portion.
 
#16 ·
Yours sounds very much like the situation I faced. FWIW, here's a link to pics of the jury-rig I came up with that did work to extract my broken plug:

https://drive.google.com/open?id=0B9SkSAEPQcsmVVdON2FDN281NVU

Took several attempts before I came up with a wire harness that held up to the impacts; I wound up using stainless wire - just what I had lyin' around that finally did the trick. First it was necessary to remove the tip and the threaded portion exposing the electrode rod. I don't recall that being too difficult. IIRC, after soaking the plug a while with penetrant, I was able to get it to move a bit with the slide hammer. Added more penetrant & drove the plug back down. Next time with the slide it came out further. Repeated the process a couple more times before it finally gave up and came out intact. Apologies for the poor lighting in the pics, but in the second one you should be able to see the whole contraption suspended from the g/p clamped in a vise.
 
#18 ·
Pretty sure it was an imperfect seal where the end of the body of the plug seats against the small aperture into the c/c. Leakage of hot combustion gases over time led to massive carbon buildup above the seat. It's not exactly an oxygen rich area above the seat, so incomplete combustion leaves a lot of raw carbon. At least that the best my imperfect understanding can come up with. Before I acquired the car some genius had put a wrong plug with a bigger tip in #5; third pic shows a comparison between the broken and a new plug. It had the wrong voltage rating as well. I think the aforesaid genius also had to drill out the aperture a bit just to get the plug installed. Fortunately there was sufficient material remaining to allow me to re-establish what I hope is a positive seal.

If the body is broken as was mine just below the threaded portion I doubt you'll be able to get it out intact, but good luck with that.
 
#19 ·
Good news!! - got the stuck glow plug out- After 48 hours of soaking with PB and fully un-threaded from head, I started motor and warmed it to 80C revving to 2000 RPM occasionally, I placed a small piece of rubber directly on top of the plug and shaped it upside in an down "U" shape over the plug, then covered the plug area with a rubber matt, I shut off motor a few times and plug was much easier to turn after engine warmed up.

I noticed the matt move up slightly and the motor missed slightly, shut it off and plug was even easier to turn. Started up again and rev'ed a few times and motor had consistent missing, shut down and plug was very easy to turn and pulled out. Ran engine for about 30 minutes in total.

Plug had some carbon on it that came off easily with wire brush. The threads look ok inside head but the plug is difficult to push back into the hole and start threading, the inside of the hole looks black indicating a carbon build up. The holes for the other 5 plugs looked clean beyond the threaded portion. I don't want to force the plug back in. I will order the Baum reamer and look for instructions on how to use it.

The stuck plug from this #5 cylinder had a different p/n from other cylinder I checked and the electrode portion is slightly longer by about .100".
The stuck plug in Cyl #5 was Benz A0011595201- Beru #0100266005

Cylinder # 2 p/n Benz A0011595101 Beru # 0100266012

On checking a Canadian web site plug supplier it seems there is a different plug for USA & Canada vehicles, they mention Emissions as the reason, so it may not matter which one is used as I seem to have both installed . I think I will pull the other plugs again and check p/n's to compare. I think the #5 cylinder plug was and original plug.

They state;
Benz A0011595101 is for USA (shorter electrode)
Benz A0011595201 is for Canada (longer electrode)

All are 5V
 
#20 ·
That is good news! Somehow I'd gotten the mistaken impression that your stuck plug was broken like mine. Glad to finally see that wasn't the case. Looks like getting that bore cleaned out so the replacement is able to seal properly looks to be your next task.
 
#21 · (Edited)
I needed to move the vehicle and did not want to wait for the Baum reamer, so to clean the glow plug hole I used a bronze type rifle bore wire cleaning brush (410 gauge seemed about the right size) attached to a gun cleaning rod to remove the carbon, rotated the brush into the hole slowly and added a little PB into the bore as well and it came up clean after repeating 3-4 times.

Some carbon plugged the small hole at bottom where electrode slides in, so used a stiff piece of aluminum wire to clear the hole and the injector inserted just fine. The carbon looked like a fine powder not hard larger chunks, I coated the plug threads with silver anti seize an added a little on the lower portion of the plug but none on the electrode. I will pull it out in a few weeks to see what it looks like.
 
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