OM606 Glow Plug removal Tips and Tricks - Page 2 - PeachParts Mercedes-Benz Forum

Maxbumpo · #16 04-12-2016, 01:01 PM

Quote:

Originally Posted by funola

Maxbumpo, what was actually binding the glow plugs? Is it carbon after the glow plug flare seal (in the combustion area) or before the flare (in the glow plug threads)? Or both? If before the flare in the threads, it would suggest the flare was not sealing properly and allowed carbon to pack the threads.

funola · #17 04-12-2016, 01:55 PM

Quote:

Originally Posted by Maxbumpo

I am not seeing this description clearly. The (pre-chamber end) would be the tip end only?

Here's a pic of the glow plug. Where is the carbon packing?

ROLLGUY · #18 04-12-2016, 06:37 PM

Quote:

Originally Posted by funola

I am not seeing this description clearly. The (pre-chamber end) would be the tip end only?

Here's a pic of the glow plug. Where is the carbon packing?

Between the threads and the taper where it is supposed to seal. Sometimes they don't seal well at the taper, and carbon packs in the void around the main body of the glow plug. At least that is my understanding. I usually apply antiseize to this area as well as the threads.

nelbur · #19 04-12-2016, 08:48 PM

About four years ago I had a local dealer install a full set of Bosch MB glow plugs in my E 300 D. Recently I had a glow plug go bad, so I had the same dealer replace all of them with some Berus I bought. When they pulled the old plugs, #1 had carbon all over the body of the plug between the sealing step and the threads. The dealer makes a big production about reaming out the carbon, and said they anti-seize the threads, but the plug was clearly not seated properly. Ironically #1 was still working fine. So I am wondering how one can be sure the plugs are seating properly. The reamers do not seem to clean the sealing surface. I'm thinking I may do the job next time so I can be sure the seats are clean and the plugs are anti-seized from seat to threads. Does anyone have a seat cleaning tool? It ought to be easy to make something that could be hand twirled, maybe even a drill bit if the angle is correct.

funola · #20 04-12-2016, 09:16 PM

Glow plug seal not seated properly allowing carbon past the seat could be from:

1. glow plug not torqued properly
2. glow plug seat surface not clean
3. damaged glow plug seat

The glow plug seat seal can be tested by filling the outside of the glow plug where it threads into the head with shaving cream and cranking the engine a few turns while watching for bubbles. If you see bubbles in the shaving cream, the glow plug seat is not sealing.

Maxbumpo · #21 04-12-2016, 09:33 PM

Is anyone else unable to attach files to posts?

funola · #22 04-12-2016, 09:39 PM

I never attach photos to posts. I always upload files/ pics to photobucket and copy/ paste the link.

ROLLGUY · #23 04-13-2016, 10:10 AM

Quote:

Originally Posted by Maxbumpo

Is anyone else unable to attach files to posts?

I tried the other day and was unable to do so. I got the "file upload failed" message.

funola · #24 04-13-2016, 11:36 AM

Quote:

Originally Posted by ROLLGUY

Between the threads and the taper where it is supposed to seal. Sometimes they don't seal well at the taper, and carbon packs in the void around the main body of the glow plug. At least that is my understanding. I usually apply antiseize to this area as well as the threads.

Thanks. Like this extreme example? Seems like if the taper seals properly, glow plug breakage on removal should not be a problem on the 606?

michakaveli · #25 04-27-2016, 04:43 PM

Great post Maxbumpo... I replaced all (6) glow plugs recently as well. My #4 plug was being the difficult one. I rocked the plug back and forth, CCW and CW. When it got tight, my heart sank and deceided to warm up the engine. The heat helped immensely! I also used a "penetrating" solution .... 50/50 mix of acetone & ATF on the outer portion of the plug. This penetrating solution I picked up from Popular Mechanics some time ago and has worked wonders in other situations such as this.

I cleaned out the bores with the reamer from PeachParts I bought years ago.... Then followed up with a good blasting of compressed air in the glow plug holes with cleared out a good amount of carbon (mostly #4 plug).

ESchwab · #26 04-27-2016, 06:54 PM

I have a '98 E300dt and changed the glow plugs three or four years ago. I think it is important to use the smallest 12 mm socket you can find. I used a craftsman 12 mm quarter inch drive deep socket on glow plugs 2 through 6 and had no trouble getting them out. I sort of stumbled onto using it, because it was the only socket I have that I could get onto 5 (or perhaps) 6 due to obstructions.

I used a somewhat larger 12 mm 3/8 inch craftsman deep socket on the number 1 glow plug and had a devil of a time in getting it out. I used it due to obstructions. If I had used the quarter inch socket, I would have needed a couple of extensions. I was afraid they would have come apart, and I would have trouble getting the socket out. In retrospect, I think the problem may have been binding of the socket against the seat of where the glow plug screws in and against the sidewalls (the sort of tube) that surrounds the glow plug. I think it is important to push socket all the way in and then pull it out a small fraction of an inch before starting to unscrew the glow plug. This prevents some of the binding. There is also less binding with a smaller socket.

One of the people who used to comment regularly on the MBCA website recommended using a 3/8 inch 12mm snap-on socket that is a bit smaller than its 12 mm regular deep sockets.

I didn't do the job on a hot engine, because removing the intake manifold is such a job. I figured I'd burn my hands getting it off and that the engine would cool by the time I removed it.

I've got to say though that Max Dillon knows a lot more about diesels than I do.

300GD · #27 12-22-2016, 12:23 PM

Last weekend I tried the glow plug removal on my car (95 E300). At the end of the ordeal I was left with #1 and #6 plugs fully unscrewed, but still stuck in the head. I removed the stuff that was in my way for pulling on #1 with vice grips, but I haven't been able to pull it any farther out. That technique isn't even going to be an option on #6, since the oil filter canister is in the way.

So I was thinking about my options and was wondering if anyone has tried reassembling the engine and starting it up, to see if engine compression would help push out the stuck plugs. My biggest concern with that is that the GP could become a projectile if dislodged.

The other thing I considered is to use a pry bar to pull on the plugs. The concern there is I would be potentially using a large unknown amount of force on the plug, which goes back to the fear of breaking one.

pimpernell · #28 12-22-2016, 02:17 PM

"The other thing I considered is to use a pry bar to pull on the plugs. The concern there is I would be potentially using a large unknown amount of force on the plug, which goes back to the fear of breaking one.[/QUOTE]"

I don't think the pry bar approach would be a wise thing to do. I know in my case, I had two plugs that were unscrewed, but would not come out. I was able to use a deep socket, and just kept turning them back and forth using plenty of PB blaster. I was able to move the plugs about one half inch in each direction, but after about a day of soaking and moving the plugs they finally came out in one piece. By using the deep socket, each time I moved the plug, I would apply a slight upward pressure and stayed within the 40 to 45 NM. Worked on a lot of cars in my life, but this glow plug job gave me more white hairs than any other job I ever did. Good luck

300GD · #29 12-22-2016, 04:08 PM

Thanks for the input, and I agree this is one screwed up job! Almost makes me wish I could swap this motor out for a good old OM617.

Could you elaborate on what you were saying about using slight upward pressure while turning?

pimpernell · #30 12-23-2016, 01:34 PM

Quote:

Originally Posted by 300GD

Thanks for the input, and I agree this is one screwed up job! Almost makes me wish I could swap this motor out for a good old OM617.

Could you elaborate on what you were saying about using slight upward pressure while turning?

I was using an extension on the deep socket I was using, and whenever I turned the plug back and forth I would also use a slight pulling up on the extension while turning. Its a little bit of a juggling act with one hand holding the socket on the end of the extension and the other hand keeping the top end connected to the wrench.

Those two plugs were so carbon bound that they would squeak when being moved in either direction.