I'm in the middle of changing all of my glow plugs. Manifold is off and I got five of them out rather easily, reamed the holes and put five new ones in their place. #1 won't budge and I'm afraid to apply too much force for fear of breaking it off in the head. #1 was the bad one, so I can button everything up and leave it alone. Interesting thing is that this plug was the only one replaced by the dealer about 25,000 miles ago. So should I just leave things well enough alone? #1 is the only plug that can be removed with the manifold in place, but if it won't come off now, what's it going to be like when it does have to come out? How hard/expensive is removing a broken off glow plug? I understand that Mercedes has come up with a tool/procedure for doing this without removing the head. Anyone have an address for that information? Any other suggestions welcomed. I've been spraying it with Kroil for the past two days BTW. Wonder if running the glow plugs through a heating cycle would do anything useful?

Thanks.

Len
'99 E300TD 71,500 miles

My previous post was supposed to say the "Glow plug #1 was NOT the bad one." It was glow plug #2 that was bad and I got it changed. Sorry for the major error there.

Len

sokoloff,

I always found that heat would loosen frozen threads. Try heating the GP with a acetelene torch.

Put new ones in using a neversize compound. Steel tends to solid state diffuse in aluminum because of the electrochemical difference. This causes an electron flow and the metals fuse together.

If MB built a real quality product, they would put a steel insert in the head.

If you can't get it out, leave well enough alone. It might work for a long time.


P E H

Get some Aero-Kroil and soak the GP thread area liberally with the stuff a few times a day for a couple of days, and you should be able to break it loose.
Takes a while, but it beats the heck out of doing surgery

--------Robert

It's not the threads that sieze, it's all the carbon packed around the four-five inches of glow plug below the threads. I've had to wrestle those things out with a huge set of vice grips _after_ they were completey unthreaded.

I recall one of our resident tech experts - perhaps Donnie or M.B. Doc? - posting that he would pull the injector and fog the cylinder with a solvent, then let it work overnight.

I too have read that MB has special tools and procedures for removing broken glow plugs. However, I suspect it would be a challenge to actually find a dealer that has both the tools and knowledge within their inventory...

- JimY

It was DR.DIESEL, in this thread. I haven't seen a post from him a quite a while. So, for those who don't know him, DR.DIESEL is an MB dealer tech.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

I've had a fe w that were real sticky and didn't want to come out from the stuff on the end, once it started spinning, I took a set of long needle nose pliers and set then against the backside of the hex seuface of the glow plug and applied leverage while turning the glow plug out. So far it's worked each time.

----------Robert

If that glow plug is fine and you can get at it with the manifold on I would just leave it alone. It might not go bad for many years and if it does you can always deal with it then.

__________________
2006 CL500
1969 280SE
2023 Ram 1500
2026 Genesis GV70
2007 Tiara 3200

From another forum:

New Info on Glowplugs Seizing in the Head
As a follow-up to my $2600 glowplug adventure in December (http://mbca.cartama.net/showthread.php?s=&threadid=1528), here's some new info.

(This is especially interesting as both the Service Manager and the regional MBNA service rep told me then that this was NOT a common problem.)

Quote:
"Unfortunately this is a very common issue. Common enough that MBNA recently issued a Service Bulletin ( document no. P-B-8.20/134 dated January 2004) announcing that a repair kit for damaged glow plug threads and/or broken off glow plugs in the cylinder head has been developed. As a result, the replacement of the cylinder head in almost all cases is no longer required.
The repair kit can be ordered as Special Tool, p/n 611 589 00 99 00 and this kit is applicable to diesel engines 601, 602, 603, 604, 605, 606, 611, 612, 613, 628, and 646.

Seizing of glow plugs (also spark plugs) is inevitable when istalled in cylinder head for a long period of time. One technique I know that so far works all the time is by removing the glow plugs when the engine is at operating temperature and using 3/8-inch impact wrench set at very low torque."

"Seizing of glow plugs (also spark plugs) is inevitable when istalled in cylinder head for a long period of time. One technique I know that so far works all the time is by removing the glow plugs when the engine is at operating temperature and using 3/8-inch impact wrench set at very low torque."

Tough to do this at "operating temperature" on the 606 when the intake manifold has to come off. This probably works well on the older diesels like the 617. My 99 E300 has 72K on the odometer and I haven't had a GP problem yet. I'm saving my $$ for when the time comes.

__________________
99 E300 133K
98 ML320 99K
87 Saab 900 Turbo Conv 123K

I hope i will not have any problems when i change mine out later this year. I looked through the records and did not find one stating that the glow plugs have been changed. Hopefully they have been though...not looking forward to having one break off.

__________________
2002 G500 74K
1998 E300 200K and rising
1995 S600 73k


"Some people spend an entire lifetime wondering
if they've made a difference. The Marines don't
have that problem."-Ronald Reagan

"Never tell people how to do things. Tell them
what to do and they will surprise you with their
ingenuity."-General George S. Patton

W140,

Why replace the GP when they are working OK? Sounds like a case for the expression "If it ain't broke, don't fix it".

P E H

Do 603 engines have the long GP?

P E H

No, the 603 is a 2 valve per cylinder design. The 606 being a 4 valve design, has the prechamber oriented vertically over the center of the combustion chamber. But the glow plugs still go in from the side, so they have to be extra long to reach the prechamber.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

P E H,

Since I don't know when they were last changed, I'd rather not take the chance of leaving them in longer. I dont remeber who said it, but they recommended getting them out because the longer they are in there, the higher the chance of them getting stuck. Besides, I want to clean the intake manifold, I might as well change them while its off.

__________________
2002 G500 74K
1998 E300 200K and rising
1995 S600 73k


"Some people spend an entire lifetime wondering
if they've made a difference. The Marines don't
have that problem."-Ronald Reagan

"Never tell people how to do things. Tell them
what to do and they will surprise you with their
ingenuity."-General George S. Patton