I am new to this Forum, having found it as a result doing some searching for a problem that I have. First let me say that after looking at this Forum I thing that its great!

Now on to my problem with my wifes 1995 E300D, with 80K miles on it. An other glow plug went out (have replaced 2 other ones in last year). Unlike the previous 2 times this one came out with difficulty. After doing some research I found out about the carbon problem with glow plugs. I thought it was time to change them all out, so started to remove them all. I had to soak 2 of them but they did come out it one piece. Soaked the 3 that were left over for the night. Picked up the next morning got one more out without a problem, but when I tried to remove the front one it was hard like some of the others, but unlike the others it sheared off just above the threads of the glow plug.

I have started read the factory manual to see what is involved in taking the head off to do a repair. I would like to get sanity check on this. I have rebuilt engines in the past but the last Mercedes
Diesel that I rebuilt was a 1966 200D.

Thanks Bill

Hello Bill A
Call your local machine shops that do engine work.
Ask them if they will extract the remaining glow plugs; with the engine in the car, if you have the car towed to their shop.
You should be able to find a couple of machine shops willing to do the work.
If the machine shop does race engines, it can pull the glow plugs easy.
The big question; is finding a machine shop willing to do it with the engine in the car.
Have a great day.

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I had not considered this. Looks like I might have to remove fuel filter and or IP to give them room to work. Will make some phone calls tomorrow

Bill

...also... I had the AllData DIY subscription for a day and read that Mercedes now has a procedure and tool set for extracting broken glow plugs without removing the head.

This was an official bulletin so one path you should at least investigate is getting the dealership's quote.

good luck

__________________
Mark Herzig
1995 E300D 153K
1985 300D 142K (sold)
1979 450SL 122 miles (sold)
1992 500E 127K (sold)
1987 300SDL 132K (sold)
1986 300E 161K (sold)

Can this systematic problem be precluded by removing the glow plugs when the car is young and treating the threads with antisieze? It seems like this bit of preventive maintenance can go a long way in reducing problems later.

__________________
95 E320 Cabriolet, 159K

Antiseize won't help. It's not the threads that lock up the glow plug, it is carbon packed around the shaft of the plug below the threads. The glow plugs on the OM606 are about six inches long, so there's plenty of surface area for the carbon to grip and hold tight. I've had these things completely unthreaded, and still had to spend a day soaking them in penetrating oil to get them out.

I went through the same repair on my 1998 E300. I paid to have it done. After trying for a few days to remove the plug with the head in situ, the mechanic pulled the head and finished the job on the bench. In a scary side note, all three of the machine shops he normally uses refused to work on the head.

I sold the car a few months later rather than risk another $2500 repair in the future. The E300 is a wonderful car, but I think the gasoline versions make more sense, given this achilles heel of the OM606 diesel.

- JimY

I've just bought my first Merc, it's also a '95 E300D with 95,000 miles. These glow plug problems I read about are beginning to make me wish I'd bought something else.

However, one thought I've had that I've not seen mentioned is the use of caustic soda to dissolve the carbon. It works great on carbon/soot in 2 stroke exhaust pipes. So why wouldn't it work to loosen the carbon around the glow plugs, assuming you soaked the glowplug with a small amount ? Would it destroy the aluminium or trash the inside of the cylinder, or would the carbon be too hard to dissolve due to the temperature in the cylinder ?

Has anyone tried using this stuff ?

__________________
'95 E300D

When I went through this trauma, I actually put the antiseize on the shaft and the thread - can't see how it would hurt.

-Dan

__________________
1996 (W210) E300D 86K - Traded in for a Lexus
1992 (W124) 300D 2.5 Turbo 202K - Sold
1983 (W123) 300D, 146K - Sold
1970 280S, 263K - Sold - Beginning of addiction

Hi Bill A,
I broke a glow plug on a 605 (same engine only 5 cyl). Like you I looked at all the alternatives. Im still undecided about how to tackle it, but she still started OK 1 plug down through Dec. & Jan. OK we didnt have a very severe winter, worst was -4C. but apart from a bit of smoke & rattle for 20 secs, I dont like treating my pride and joy like this but the thought of taking the head off ........
Even with the head off it might not be that easy. My understanding of it is that you wont be able to see the hot end of the plug till the pre chamber is removed, & you cant remove the pre chamber till the glow plug comes out ! Experts very welcome to comment !.

Regards Peter

OK, I'm a newbie when it comes to the internals of the 606 engine...but why would it be so difficult to pull off the head? Is there that much labor. Granted I wouldn't wish extra work on anyone...is there that much involved.

To Everyone who has replied:

I have been looking at my options, I have not found a machine shop that will work on the head while it is in the engine, they say thats what Repair Garages are for. The Service Rep at the local Mercedes Dealer spent some time looking for a bulletin with a procedure and tool for removing it inplace and could not find one. He also talked with 8 of his mechanics and they had not heard of it either. He also said that after head removal they don't even mess with it themselfs and send it to a machine shop. At this point I have pretty much resigned myself to taking the head of and taking it to a machine shop. I have the CD manual and this looks like it will be a fun job. I have looked at all the special tools that I need and have ordered all the ones that I don't have. It looks like the most fun part has to do with the timing chain. Since I have 80K miles I think that I might replace the chain tensioner and plastic guide rail. I will check the timing chain streatch and replace if needed. Anything else I should check or replace? Up to this point engine has run fine and got normal mpg.

Bill

I just loaded up the CD....whew, that does look involved.

Hope my GPs come out easily when the time comes.

Good luck and on the bright side I doubt you'll have trouble selling those special tools after your done with them.

Chuck

bill
i recommend you replace all nylon fuel lines around the fuel filter and inj pump (almost garranty they will leak) those and the delivery valve seals.
i just did a headgasket on a 606 last month, its not too bad.
goodluck