Glow Plug - One or All? - Page 2 - PeachParts Mercedes-Benz Forum

aklim · #16 12-20-2007, 02:48 PM

Quote:

Originally Posted by Skid Row Joe

Why miss-out on all the fun you'll have pulling the intake manifold each time one glow plug goes bad?

Some here live to pull their manifold as often as they possibly can.

I've only had to pull the manifold 3 times. Once was done by the dealership that sold me the car. Shutoff valve was leaking. What did those geniuses do? Change the valve but leave the O-ring. Of course it leaked. Changed all the hoses and it was fine. The other time was for the glow plugs and the last time was when I took out the injectors for testing, I decided to check the GPs.

nhdoc · #17 12-20-2007, 02:52 PM

Quote:

Originally Posted by Skid Row Joe

Why miss-out on all the fun you'll have pulling the intake manifold each time one glow plug goes bad?

Some here live to pull their manifold as often as they possibly can.

Is this comment supposed to add something constructive to the debate?

Basically there are two types of people here...people who think it is worth the risk of breaking a GP off to have the peace of mind to know they all come out easily Vs. those who want to reduce the risk as much as possible of having to face breaking off a stuck plug so choose to postpone having to remove them for as long as possible.

The only argument you can make for position number one is if you feel that plugs that have been in place for a period of time, say 2 or more years, stand a greater chance of developing "stuck plug syndrome" than if they are removed periodically and replaced. Personally I do not subscribe to this theory and choose to postpone the "fun" of facing a broken GP until it is absolutely necessary, if ever. I base my theory on my own experience of havng replaced all 6 of mine after I bought my car in 2005. They were all originals and 6.5 years old and I was able to get them all out, though they squeeked and squealed as we unscrewed them since the carbon on their ends was tightly packed against them.

If I had known then what I know now I would not have tackled that job since it was pure luck that I didn't break one off then and feel that if they came out last time after 6.5 years they most likely will again...why pull them every 2 just to see and risk having trouble that I might never have to face if I decide to sell the car or crash it before the next GP fails?

nhdoc · #18 12-20-2007, 02:53 PM

Quote:

Originally Posted by aklim

I've only had to pull the manifold 3 times. Once was done by the dealership that sold me the car. Shutoff valve was leaking. What did those geniuses do? Change the valve but leave the O-ring. Of course it leaked. Changed all the hoses and it was fine. The other time was for the glow plugs and the last time was when I took out the injectors for testing, I decided to check the GPs.

And, as we all now know, you don't have to pull the IM to change the SOV so those "genuises" didn't even know they could easily get to it from the washer bottle's location by just moving it out of the way.

aklim · #19 12-20-2007, 02:57 PM

Quote:

Originally Posted by nhdoc

And, as we all now know, you don't have to pull the IM to change the SOV so those "genuises" didn't even know they could easily get to it from the washer bottle's location by just moving it out of the way.

Please, Marty. If they reuse the shut-off valve O-ring, you want them to do it the way we know? Aren't you asking too much? To make sure they had the right stuff, I bought them at my dealership and brought it there for them. At the end of it, I turned in the invoice and they paid me for the parts.

whunter · #20 12-20-2007, 03:04 PM

11-16-2007, 11:12 AM
vox_incognita
Registered User Join Date: Mar 2003
Posts: 194

From www.beru.de :
"Installation Information: Cover glow plug thread and -shaft with mounting grease, (GKF 01 - Order No. 0 890 300 034), before fitting to enable easier removal and prevent corrosion.
Tightening Torque [Nm] 22
Failure Moment [Nm] 45 "...

Good luck!

aklim · #21 12-20-2007, 03:05 PM

Quote:

Originally Posted by nhdoc

Is this comment supposed to add something constructive to the debate?

though they squeeked and squealed as we unscrewed them since the carbon on their ends was tightly packed against them.

why pull them every 2 just to see and risk having trouble that I might never have to face if I decide to sell the car or crash it before the next GP fails?

His replies are often that way. Not too much content and acerbic.

How did you determine that? Like I said, I had the head out and it was not packed with soot. Just trying to see whether that is a real issue or not. OTOH, if that is a real issue, should we be cleaning it since a soot packed pre-chamber might not be the best thing for combustion?

I pulled mine in 60K after I did the head. Knowing what I know now, I would leave it for 4 years really. If it is still good then, I might extend it further.

nhdoc · #22 12-20-2007, 03:12 PM

Quote:

Originally Posted by aklim

How did you determine that? Like I said, I had the head out and it was not packed with soot. Just trying to see whether that is a real issue or not. OTOH, if that is a real issue, should we be cleaning it since a soot packed pre-chamber might not be the best thing for combustion?

The way the plug "feels and sounds" is the best way I can describe my opinion of what was holding it and it did not feel like stuck threads. The sound like fingernails on a chalkboard comes to mind as you turned the plug. You could feel the vibrations coming down the plug from its end, not near the threads but closer to the tip. I can't describe it except to say it is not the same as unscrewing a bolt which is rusted or stuck...if you experienced it you maybe can describe it better than I can, but my opinion is that mine were not suffering from any problem with the threads...it was a binding from deeper down.

aklim · #23 12-20-2007, 03:15 PM

Quote:

Originally Posted by nhdoc

The way the plug "feels and sounds" is the best way I can describe my opinion of what was holding it and it did not feel like stuck threads. The sound like fingernails on a chalkboard comes to mind as you turned the plug. You could feel the vibrations coming down the plug from its end, not near the threads but closer to the tip. I can't describe it except to say it is not the same as unscrewing a bolt which is rusted or stuck...if you experienced it you maybe can describe it better than I can, but my opinion is that mine were not suffering from any problem with the threads...it was a binding from deeper down.

Did you clean it out? Are you going to have to do regular maintenance and clean it out?

kerry · #24 12-20-2007, 03:32 PM

Quote:

Originally Posted by nhdoc

The way the plug "feels and sounds" is the best way I can describe my opinion of what was holding it and it did not feel like stuck threads. The sound like fingernails on a chalkboard comes to mind as you turned the plug. You could feel the vibrations coming down the plug from its end, not near the threads but closer to the tip. I can't describe it except to say it is not the same as unscrewing a bolt which is rusted or stuck...if you experienced it you maybe can describe it better than I can, but my opinion is that mine were not suffering from any problem with the threads...it was a binding from deeper down.

Would a solvent introduced through the injector hole dissolve the carbon holding the tip?

aklim · #25 12-20-2007, 03:33 PM

Quote:

Originally Posted by kerry

Would a solvent introduced through the injector hole dissolve the carbon holding the tip?

I wouldn't try that. It might seep past the rings.

nhdoc · #26 12-20-2007, 03:37 PM

Quote:

Originally Posted by aklim

Did you clean it out? Are you going to have to do regular maintenance and clean it out?

I just used a reamer but don't know how much good that does since it does not look any larger than the plug other than at the very tip of the plug...basically I am keeping fingers, toes and legs crossed until I next have to tackle one. I did use antiseize on the plug...just as belt and suspenders approach...but like I said my threads felt and looked just fine.

aklim · #27 12-20-2007, 03:45 PM

What about taking out the prechambers and cleaning them?

Diesel911 · #28 12-20-2007, 04:06 PM

Quote:

Originally Posted by nhdoc

The way the plug "feels and sounds" is the best way I can describe my opinion of what was holding it and it did not feel like stuck threads. The sound like fingernails on a chalkboard comes to mind as you turned the plug. You could feel the vibrations coming down the plug from its end, not near the threads but closer to the tip. I can't describe it except to say it is not the same as unscrewing a bolt which is rusted or stuck...if you experienced it you maybe can describe it better than I can, but my opinion is that mine were not suffering from any problem with the threads...it was a binding from deeper down.

I had 2 plugs make this sound (OM 617.952 engine) when I changed the glow plugs. This prompted me to obtain a glow plug reamer. I went back and removed the plugs and reamed out the carbon which is an easy job on my engine. I considered that sound to be a warning sign that at lest 2 of my plulgs could have been on there way to being siezed.

barry123400 · #29 12-20-2007, 07:54 PM

Not that I own one of these engines. If I did I would consider filling with a solution like marvel mystery oil and allowing to soak for days. That might dissolve or soften enough carbon to ease the removal somewhat. A help if it even just softened the carbon to some degree. . . The soaking carbon has to soften before it dissolves. Only the penatration depth/rate of the solvent into the carbon is in question here.
Sure some of the junk will go by the rings so perhaps do the glow plugs when an oil change is due. There has to be a less painful way than breaking off plugs and pulling heads.
The only real problem is the soaking takes time. So is basically not a garage option.
Yet if you have access or own more than one car and do your own work what is the downside? It is proven that the marvel mystery oil dissolves carbon. Mind at a slow rate. The rate of softening again is an unknown. Or perhaps someone out there does have the rate/depth/time equation.
Some other safe chemical might even be quicker.. Soft dissolved carbon will not hurt the engine.
If you were bound and bent to change them. They operate at a nominal 12v. What is going to happen to the carbon if you push each plug to 18-24 volts? Hot enough to burn it off? Is the heat too intense for the alloy head if the plug does not burn out?
Just a thought but again it would take quite a bit of knowledge and perhaps an old cracked head to do experiments on before even really considering a higher voltage approach.
You could even get the estimated time of dissolution or softening of the carbon with safe chemicals and the old cracked head. . I know the marvel oil works to some extent.
A member some time ago stood an old injector in a shallow container of marvel oil . I believe that member reported seeing a stream of black leaving the injector area in a couple of days time. That had to be the carbon around the nozzle dissolving. What is important and the member did not deal with. Was the remaining carbon still as hard to remove or getting softer as well?
If it tends to soften the carbon overall and I suspect it might. Rather than just the surface that is in an advanced state of dissolution that could be one answer to this miserable situation.

240Joe · #30 12-20-2007, 08:03 PM

If the car starts fine when cold, don't do anything.

Don't even change the "bad one".

When it starts not starting...hehehehe....then you've probably lost 2 or 3 or 4 and you can just change them all.

240Joe