99 E300 Turbodiesel Glow Plug Help. Urgent - Page 2 - PeachParts Mercedes-Benz Forum

Rick Miley · #16 12-22-2004, 10:10 AM

$10? Hmmm, I want to know what your source is for glow plugs.

Brian Carlton · #17 12-22-2004, 11:05 AM

Quote:

Originally Posted by aklim

New day, same results. Hitting them with more PB Blaster and hoping for the best. Seems like it is just stuck. Won't turn and I don't want to use a breaker bar or a pipe on my 3/8 craftsman rachet because I am afraid of breaking it off in the head.

If they won't turn at all, is it possible that you are being conservative with the 3/8 ratchet? Can you put a torque wrench on it to tell how much torque you are applying?

I would think (and this is just an estimate) that the plug could handle at least 60 ft.-lbs. I'm not sure of their internal construction, however, a 1/2" cap screw is good to 120 ft.-lbs. I would think the threads on the plug are something around 12 mm.

60 ft.-lbs. would be difficult to apply with a 3/8 ratchet.

One other possibility:

Get an impact wrench and lower the air pressure down dramatically. Test the wrench on another fastener to ensure that the maximum torque you can get out of the wrench is about 50 ft.-lbs. Be positive of this. Then set the wrench up on the glow plug and let it hammer away for a few minutes.

If you heat the plug with a propane torch before you do this, I am fairly sure that you will be successful.

pberku · #18 12-22-2004, 11:23 AM

Unless the plugs are totally dead there is something else you can try.

Run 12V directly to one of the plugs, and let it heat-up for at least 2 Minute. Try removing it immediately after. If you get a hefty spark when you connect the 12 volts, that's good. You know that that plug still has some life in it. If not, the plug is dead.

If that does not work, an UNEXPLORED idea, is to connect 24V (2 * 12V Batteries in Series) directly to the plug, If the heating element is still working, even a bit, the super heated plug may than be more agreeable to come out.

At worst (actually at best), you may cause the plug to disintegrate, with its pieces falling into the pre-chamber. If that happens, the plug will than easily come out. The pieces can later be extracted by removing the pre-chamber. Certainly easier, and cheaper, than removing the head.

As I said, I have not heard of anyone trying this, but I don't see a downside to it. It may just work. Can someone else comment?

Phil

aklim · #19 12-22-2004, 02:33 PM

Quote:

Originally Posted by Rick Miley

$10? Hmmm, I want to know what your source is for glow plugs.

I will take out the gasket and replace it for $10. The plugs will be loosened and cleaned and new anti-sieze will be applied.

TimFreeh · #20 12-22-2004, 05:29 PM

Quote:

Originally Posted by pberku

If not work, an UNEXPLORED idea, is to connect 24V directly to the plug, If the heating element is still working, even a bit than, than the super heated plug, may than loosen. At worst, you may cause the plug to disintegrate, with its pieces will falling into the pre-chamber. If that happends the plug will than easaly come out. The pieces can later be extracted by removing the pre-chamber. Certainly easier than removing the head.

As I said, I have not heard of anyone trying this, but I don't see a downside to it. It may just work. Can someone else comment?

Phil

This is a great idea - As long as the plug is working when you try to remove it.

aklim · #21 12-22-2004, 07:23 PM

Update: all but one GP has come out. The last one broke off just below the nut. Trying to drill it out with an easyout isn't working. Someone qouted the MB procedure for stuck GPs. Anyone know what that procedure is and can spell it out?

Hatterasguy · #22 12-22-2004, 08:29 PM

Ouch, I wasn't told anything about the $900 kit just that they didn't use it or seem to think it was worth much. If you know a good dealer you can talk to call them and ask them about the kit.

If the threads are completly free and you won't damage them maybe just drilling the whole plug out and use a small punch to knock the rest into the pre chamber. Then pull the pre chamber and clean everything up. The reamer tool could probably help to.

aklim · #23 12-23-2004, 12:46 AM

I thought the GP screws into the head? If so, you would need to pull the head, right? How do you take out just the prechamber? The tip is still on and we cannot take it out even with drilling. If we did drill out the reminants of the plug, it would take a long bit and also wouldn't the reminants fall into the combustion chamber along with the tip?

JimSmith · #24 12-23-2004, 01:57 AM

aklim,

You are correct, the plug enters the side of the head. The prechamber and injector are located "dead center" above the the piston. This is a significant difference from the previous designs, especially the 616 and 617 series Diesels with cast iron heads. Those engines had prechambers that were installed at an angle, from the side of the head where the glow plugs are installed. The basic geometry results in a shorter glow plug because it does not have to reach to the center of the cylinder bore.

In all cases the hot part of the glow plug is the part that is exposed inside the prechamber. The rest of the glow plug is not intended to be heated because the barrel portion is not able to contribute to the combustion process since it is buried inside the bore in the head where no fuel is supposed to burn.

The prechamber has an array of smaller holes that lead to the combustion chamber above the piston. For particles to fall into the combustion chamber above the piston they have to be pretty small to fit through these holes. You might try taking the injector out and pouring some STP or other thick, oil based stuff in the prechamber before the drilling operation to make the particles stick inside there. When you finish the job you can remove the prechamber and either clean it or replace it.

The way it works is the piston comes pretty darn close to the bottom of the head at the top of the compression stroke. The Diesel fuel is injected at the desired point in the compression stroke, into the prechamber, where it ignites. The burning fuel and air exits the prechamber through these small holes to the volume above the piston, where the combustion is completed. In a cold start the glow plug provides additional heat to ensure the fuel begins to burn as it is injected.

It is postulated the problem you and others are having is the soot that is produced eventually gets packed around the glow plug, effectively cementing it to the aluminum head. If this is the mechanism, a longer bore that fills with soot, that siezes the plugs it might be worth warming the car up, replacing the fuel filter with a new one filled with Lubro-Molly or some other additive like RedLine that promotes reduced soot production and then giving it a serious Italian tuneup just before trying to loosen the plugs. It may be possible to burn/blow away the soot deposit. It is also a good idea to give these things an Italian tuneup regularly anyway.

Anyway, seems this problem is another one of those unanticipated consequences of trying to "socialize" our Diesels. These newer units are very civilized compared to the older ones, and they deliver great mileage while offering acceleration performance like the larger displacement gasoline engine. One of the consequences of the combination of formerly un-Diesel-like grunt, smoothness and smokelessness, with expected Diesel-like efficiency is apparently the awkward "everything under the intake manifold" design, and some detailed mechanical design compromises that are costing long term owners some concern. Like the glow plug problem.

Good luck and keep us informed. Jim

aklim · #25 12-23-2004, 02:06 AM

How do you remove the prechamber then? If the prechamber is part of the head, I would think that you need to remove the head, right? I see the head on the passenger side with the exhaust manifold bolted on it and on the driver side is the glow plug area with the fuel lines. Gilly might just have a clue when he comes to look at it again, assuming I can convince him to come up to Madison after what happened today. He got out the other two plugs and had a problem with this one and basically ran out of time.

aklim · #26 12-23-2004, 02:19 AM

Quote:

Originally Posted by JimSmith

aklim,
When you finish the job you can remove the prechamber and either clean it or replace it.

This is the part I am not sure of. How do you remove the prechamber seeing as it is part of the head. I can take out the injector and the other glow plugs but I am not sure how you unbolt the prechamber so you can remove it unless it is not part of the head. If it is part of the head, you have to remove the head too right?

JimSmith · #27 12-23-2004, 09:26 AM

aklim,

Sorry for being hard to understand. The prechamber on the 606 may be different than it is on the 616 (240D) so this may not be exactly accurate but I have no reason to suspect it is vastly different. Someone with more specific information will have to speak up if that is the case. On the older engines the prechamber is a separate part that is pressed into the head and then locked in place with a threaded locking ring. The injector threads into the prechamber along the axis the unit was installed into the head. The glow plug comes in from the side and through a hole in the prechamber that lines up with a hole in the head for that purpose. You get them out by removing the injector, the locking ring and using a prechamber puller tool from MB. The are installed using the same basic tool. Hope this clears things up a little. Jim

sokoloff · #28 12-23-2004, 09:57 AM

It is unlikely that you will have to remove the prechamber, although I asked the same questions you are asking when I ran into this. There is a slide hammer kind of a tool that is used to remove the prechamber.

I just replied to oyur other thread at http://www.peachparts.com/shopforum/showthread.php?t=111028.

Len

hughet · #29 12-23-2004, 10:52 AM

There is a post on the MBCA forum that may help you. Go to http://mbca.cartama.net/showthread.php?s=&threadid=4249

Hatterasguy · #30 12-23-2004, 10:47 PM

If the 606 is like the 603 which it seems to be, a prechamber tool is needed to pull them. Look at it this way the head has to come off anyway so try everything that you can to avoid it. With the prechamber out anything that has fallen into the cylinder can probably be blown out with compressed air. I would think that drilling the plug would weaken it enough to allow the prechamber to snap it as you take the chamber out. You may need a new prechamber but their under $100 last time I checked.

I don't know I am just throwing out every idea I can think of in the hope that one would help. Next week I am helping W140 S600 do this job on his 98, it looks very similer to my 603 everything is in about the same place.