E300TD glow plug stuck/broken

[sokoloff]

It was about a month ago that my glow plug saga started and now that it is nearing an end, I wanted to update you, especially those with a 210 chassis diesel.

My glow plug light and check engine lights came on on my instrument cluster. Had the code read and it indicated a bad glow plug(s). Turned out that #2 plug was bad. In order to replace any plug but possibly #1, the manifold has to come off. The general feeling is that while the manifold is off, you may as well replace them all to avoid having to go through the repair again anytime soon. So that was my plan.

Many thanks to Lightman and Rick from MercedesShop.com who did a great write up about glow plug replacement. See it at http://www.peachparts.com/shopforum/diesel-discussion/88574-finally-step-step-glowplug-change-98-99-e300-post580948.html The removal of the manifold is not that big of a deal, so I wouldn't hesitate to tackle that again.

Plugs 2 - 6 came out with no major headaches. #1 would not budge. Looking closely at #1, I noticed that there were a lot more threads showing sticking out of the head than the others. It turns out that #1 plug was replaced by the dealer about 18 months ago. It was done without removing the head. It is my theory that it was a little hard to reach and see and it wasn't screwed in all the way and thus did not seal, allowing carbon to enter and seal that sucker up solidly in the prechamber.

So I had to either leave it alone or get it out. I chose to try to remove it since at sometime someone, most likely me would have to do it anyway. How hard could it be I figured? It was in so tightly that my socket eventually rounded off the hex head. So then I went to a Snap-on socket that grabs the flats instead of the corners. Same thing - it wouldn't grab it either and just clicked around the glow plug. Next came a twist socket that grabs the hex head and digs into it while applying force. It did its job so well that it tore off the tip of the glow plug just above the threads. So now where do I go? After reading many posts on many different lists, I found out that this was not a terribly unusual occurrence and that everyone, but one person had to have the head removed to the tune of about $2600 to get this thing fixed. That one person was Alan McReynolds who was able to get his broken off plug out by drilling and tapping and pulling. BTW Mercedes has come up with a new procedure, P-B-8.20/134, and a tool, p/n 611 589 00 99 00, for dealing with this situation. I thought that maybe I'd go that route and save the expense of having to remove the head. Well, it turns out that the tool/kit lists for $1300 at Mercedes to do this job. I'm not sure exactly what the procedure is, but it wouldn't be all that much cheaper than removing the head once all is said and done.

So with Alan's guidance, I tired to do it myself. Actually, not all of it myself. After fooling with it for almost a month,my son came to visit over Thanksgiving and took it as a personal challenge to fix this. Did all of the following - drilled out the center heating element as deep as I could without drilling all the way through the end of the plug - used a drill bit a few 64ths smaller than what was required for the M8 tap. Drilled out the glow plug's threads in an attempt to free them up from the head - the shaft of the glow plug measures about 0.41 inches and a 25/64ths is just a hair under that. Tapped the inside of the glow plug shaft with first an M8 and then a 3/8th's tap. Tried threading a bolt into the glow plug's fresh threads and pulling it out. Took a blue wrench and freeze spray to the head and the glow plug. Nothing would budge it. We were at the point where we were about ready to give up and go the head removal route. My son said that as a last resort, let's try to drill the glow plug shaft out a little bigger in steps and see if that does anything. He took the first drill bit to it and in about five seconds he had the remnants of the glow plug in his hand. You cannot imagine how happy I was to see that. The next hurdle was to see if there were any threads left on the head to allow the new glow plug to screw in. We had done some serious drilling in the area of those plugs and had come very close, too close we suspected, to damaging them. Well, we tapped the hole (it's an M12 x 1.25)in the head, screwed the glow plug in and it torqued down just fine. BTW, I bought a reamer from Baum Tools, www.baumtools.com, for this job and used it to ream out the glow plug holes. #1 definitely had more carbon built up in it that any of the others.

So everything is back together now and the car runs fine and the warning lights are out. I'm not completely done with the job, however. I had to remove the fuel preheater that is immersed in coolant and am waiting for a new gasket for that. When that comes in, I'll remove the manifold again , check for fuel leaks and make sure everything looks okay before installing the new manifold gasket and buttoning it all up and not have to touch it for a long time I hope.

BTW, total cost of the job was probably not much more than $300. That includes six glow plugs at $20 each and the reamer for $54. The rest of the costs were for various taps that weren't in my set and other miscellaneous bits and pieces.

If it happens again, I think I would proceed a lot more quickly to the drilling it out stage,

I can't thank Alan and my son enough for their guidance and help. Same goes to Lightman and Rick. It is really great when fellow Mercedes owners share their wealth of knowledge and their experiences and insight.

Len

'99 E300TD 71,500 miles

[Jim H]

Congratulations, you've earned the DIY Persistence Pays Off award.

I got lucky on my SDL OM603, plug #4 and #6 came right out, no teasing. I ran the reamer and found almost no carbon build up. A little anti-sieze and the new plug is in.

It's great to read about DIY success here, I'm hoping that's what M-B wants for their autombiles.

Make me want to keep wrenching on my SDL a bit longer. Now, where did I put that list...

Best Regards,
Jim

[sokoloff]

Thanks Jim. You just cannot believe how good I felt when that thing finally came out.

I don't think any diesels besides the 606 engine have this type of a glow plug problem. Never had a problem on my 240D. Actually this car has turned out to be much easier for DIY work than I ever anticipated.

See below for what the glow plug looked like when it came out.

Len

[aklim]

Originally Posted by sokoloff

BTW Mercedes has come up with a new procedure, P-B-8.20/134, and a tool, p/n 611 589 00 99 00, for dealing with this situation.

I checked with the local MB shop and they have not come up with the procedure or the tool based on those numbers. Can anyone verify it? TIA

[aklim]

I found it.

BTW Mercedes has come up with a new procedure, P-B-58.20/134, and a tool, p/n 611 589 00 99 00, for dealing with this situation

[Rick Miley]

So are you going to have to buy the tool? Or is it available to borrow or rent?

[aklim]

Originally Posted by Rick Miley

So are you going to have to buy the tool? Or is it available to borrow or rent?

The shop doesn't have the tool or the need for it. In the last 15 years, they have only had 1 or 2 other cases like mine and the usual cure for it is to R&R the head. I will have someone from that shop take a look and see if they can fix it without doing an R&R.

[aklim]

Question about the tap. I see that the GP fits into a bolt that is M12 X 1.25 and so I got that tap. Now I tried seeing if it would fit into another GP hole but it seems too big and I didn't want to force it. Shouldn't it have slipped right in? I was going to use it to clean the threads of the other holes but don't want to make them bigger than I have to,.

[Jimmy Joe]

Originally Posted by sokoloff

Looking closely at #1, I noticed that there were a lot more threads showing sticking out of the head than the others. It turns out that #1 plug was replaced by the dealer about 18 months ago. It was done without removing the head. It is my theory that it was a little hard to reach and see and it wasn't screwed in all the way and thus did not seal, allowing carbon to enter and seal that sucker up solidly in the prechamber.

If a dealer did this, wouldn't one theoretically be able to take the car back there and demand satisfaction?
BTW, congrats on your success, and thanks for posting all the info.

[sokoloff]

Dealer guarantee is for one year parts and labor. In my case it was about 20 months and I didn't think it was worth pushing the issue.

Len

[aklim]

Originally Posted by sokoloff

Dealer guarantee is for one year parts and labor. In my case it was about 20 months and I didn't think it was worth pushing the issue.

Len

I would think that if THEY screwed up 20 months ago by not going deep enough into the hole, they should pay for the fix. After all, do I have to inspect every inch of what you do for me?

[sokoloff]

I would say that, yes, I do have to inspect every little thing that they do. That's why I try to do everything myself. It's a hassle to take it to the dealer because it ties the car up for two days usually and when it comes back, there is either something else wrong or it has to go back again because something isn'tright. And once the glow plug broke off, it was too late to raise hell with them. Even before it broke off, I think they would have had too much wiggle/weasel room. Just wasn't worth it, but I didn't think ti would take me as long to fix it either. It was a cheap fix though. They might even have tried to nick me for the $2600 head removal job. All in all, I'm glad I did it the way I did. No one to blame but me the next time either.

Len

[sokoloff]

So Aklim, have you made any progress on your broken off glow plug?

Len

[Oakundeisen]

I just went thru the dreaded Broken Glow Plug experience and I am here to tell you you CAN come out the other side. It started as a rebuild on the injector pump delivery valves (replaced O rings and copper seals). I figured I would replace all hoses, the shut off valve and glow plugs while in there. I have a '98 E300DT with 155K. Glow plugs last replaced at 90K. No light on and live in the Carolina's but now was a good time to get it done. All went well thanks to Lightmans post and then I ran into stubborn #5. It sat soaked in Creep overnite, heated with a heat gun. Eventually you just have to reef on it and of course it snapped above the threads spinning around on the electrode. Many thanks to Len (Sokoloff), Alan Reynolds and Dick for providing very good info and a PLAN.

I used a slide hammer attached to a #10 vise grips to remove the top (hex) of the glow plug. What remained was the electrode center. I then twisted the center (with Vice grips) in an attempt to snap off this center and give me a good center hole. I had dissected a glow plug and found that the center measured 1/4 almost exactly (Bosch). also found that the electrode was fused only at the bottom. That worked well and I had a good center hole to tap. First though I worked thru a sequence of bits moving eventually to 13/32to drill out the threads (mark your bit with duct tap as not to go deeper than the threads). I then used a 7mm tap and threaded the center to take a bolt. It doesn't matter what specific size you use since you supply both the tap and the nut/bolt. I went back and forth between a slide hammer (with a bolt welded on - see pic) and the 'bolt,washer puller' that Alan describes. Assemble the puller and start at it. Initially, when you first move the plug you will hear a crack and you are breaking the neck between the threads you drilled and the body of the plug. A Ratcheting Combo wrench here is indispensible. Eventually it really got stubborn when it was sticking out about an inch. The 7mm grade 5 could not take the torque and I went thru about 5 of these as they would gall, crossthread and sieze. Tapped up to a 8mm and this eventually 'dragged' it out (see pic). As the plug moves out of the head you will have to slip a socket over the puller to allow the glow plug to move into the hollow body of the socket. I used a 3/8 inch deep 14mm socket. All of the other plugs showed evidence of anti-sieze coating on the body of the plug. This one did not and it was covered in carbon. I stuffed grease covered tissue about a third a the way down the now empty plug hole and rethreaded with a 12x1.25 (common in stock for Mac, Matco, Snap-on but not in most of the sets -around $10.00), reach down with some forceps and pull the greasy wad out of the hole. The threadings will stick to the grease. I cleaned it out good with greasy Qtips and then reamed the hole with the glow plug tool. Since the glow plugs seat at the shoulder of the tip they only need 27nm (Thanks for this info Alan). I priced a Helicoil kit and found it readily available and priced at $80, luckily I didn't need to go this route. I coated the body of each plug with a liberal but not thick, even coat of nickel formulated anti-sieze, also put a film on the threads. I reassembled all and have some additional notes:

-I first used Kerosene and then Drive up - a driveway cleaner to clean my intake - worked great.
-I used bungee cords to move the injector lines out of the way during the Injector delivery valve rebuild.
-I tried the multispline extractor 1st on the broken glowplug - waste of time plus you are 'driving' against the soft alluminum of the head. - go easy. Insanity is trying the longer fluted type of extractor on this - do not do!
-as I drilled the threads out, I check the debris with a magnet for peace of mind, go slow, use a sharp bit, and tapping fluid.
-since I emptied all of my fuel lines and replaced the shut off valve I knew starting the car would be tough - crack open the main filter and top off with clean diesel. Use a mason jar that went thru the dishwaser and a CLEAN funnel, slide the filter forward till it bumps against the radiator hose and fill. I did this 2x and then the car FIRED UP!!!

Costs:

> I bought all lines, shut off valve, intake manifold gasket, spare spring, copper seals, O rings, spare fuel line shims (didn't need) and plastic fuel line keepers from my local dealer for $210 - not bad considering that the shut-off valve is around $140.
>I sourced the reamer, multi-spline socket (delivery valves) and the 14 crowsfoot for the fuel lines at Baum for $100.
>The plugs (6) cost me 137.00 on line - Bosch
>The 12x1.25 tap cost me $10 off the Matco truck

everything else I had on hand. I didn't come across the 'impact wrench burp method' until after I had snapped off #5. It certainly is counter intuitive but makes sense. I might try it next time. Considering that these break off on MB techs regularly I am pleased with the way everything turned out. RR on the head, rebuilding the delivery valves, replacing the glow plugs, fuel line RR and the shut off valve - I figure I saved thousands. It took me around 12 hrs off and on over several days. I work slow but methodical, always a good approach I figure when aiming a drill bit at an Aluminum head.

This is a great site; lots good people with a sense of community around a shared passion that is Mercedes-Benz. Thanks for the help!

Bill

[nhdoc]

Thanks for sharing the details of your innovative approach to removal. Another one to file away in the back of our heads...or better yet it might be worth summarizing and documenting these techniques in the DIY section.