Hello all,
I finally removed all the glow plugs without breaking any. Read my last post.


I am in the middle of changing the glow plugs on my E300DT. Thanks to Lightman's thorough instructions, the intake manifold removal was not that bad. Here is my story so far:

Before embarking on this project I read all the forums and tried to educate myself as much as possible. So far I have tried the following based on the many posts I read.

1) I drove the car very very very hard on the highway, using B20 and a full large grey bottle of Power Kleen additive. Initially I would see a large trail of black smoke as I gunned the engine, but in a few days the car wasn't smoking (at least noticeably) anymore. I drove the car hard in order to try to clean any carbon buildup inside the cylinders, since the carbon is responsible for seizing the glow plugs in the head.

2) After I removed the intake manifold, I sprayed Power Blaster on the glow plugs for a couple days. I didn't even put a socket on the glow plugs.

The result so far is that GP #1, 2, and 4 came out very easily. I placed the 12 mm socket on #1 first and applied force to unscrew, it suddenly snapped free. I initially thought I broke it (because that is what I expected to happen), but then realized that it was easily coming out. The same pressure and the same fear struck me with #2. When I got to #3 I knew how much pressure was needed to free up the GP, but it would not budge.

I put #1 and #2 GP back, because I wanted to start the engine and warm it up. I read in other posts, that the GPs would come out easier if the cylinder head was warm.

After mildly warming up the engine. I removed GP #4 in the same way #1 and #2 came out. Applied pressure and suddendly it gave way.

Now to my problem(s).

GP# 5 and 6 slowly began to unscrew. I am going very slow with these two, since they are at least moving. I unscrewed them approximately one turn, then screwed them back in. I have done this a couple times now, but it is not getting any easier. I hope that unscrewing and screwing #5 and 6 will eventually succeed.

I have applied higher and higher pressure (compared to the other GPs) on glow plug #3, but it hasn't moved at all. I really don't want to break any of them.

I read that I might have some luck taking the injectors out and flooding the cylinder with biodiesel in order to loosen the carbon build up.

Does anyone have any advice or suggestions??

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1998 E300 Turbodiesel 184K

if you do flood the cylinder make sure you change your oil afterward, it should just seep past the rings fairly quicky. just curious, has anyone ever tried welding onto a broken off glowplug?

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1981 300SD 512k OM603

Pretty important to change oil after flooding the cylinder with BioDiesel....

It can adversly affect lube-oil and 'polymerise'...

I wouldnt use BioDiesel. I personally would try normal diesel or even a Good long blast of WD-40 down the injector hole, and on a hot/warm engine, but make sure you get it ALL out before you start it!--we dont want to hear of a hydraulic lock and bent rod!...

You don't want to end up like this guy in the UK with his 605!- http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=5202&page=2

--About halfway down the page, broken plug, and drilled through the head casting!--

I know the plugs can break in these. What I dont know is why are these more of an issue than other cars...?

Weak plugs or just summit else??

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

I think you can safely proceed with #5 and #6 the way you are going, just go slowly and try spraying some PB in there as you go working the plug in and out slightly to get it to penetrate...it will carry into it that way.


As for #3 it might just make sense first to try it with a torque wrench and see if you are applying anywhere near what it considered the "safe limit" for them...that torque limit eludes me at the moment but can be found in other posts. I've also posted in the past that I think it is wise to try using an imapct tool on stubborn GPs. There are some low power air or electric tools which would apply the rat-tat-tat impact that I feel would successfully remove them. I bought one recently from harbor freight for $15 which is very compact and has a butterfly control allowing you to easily switch directions. I would bet a beer and a shot that it would remove your #3 in no time.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

The thought of a bent rod is making me have second thoughts about trying the cylinder flooding procedure. I am also thinking that maybe the top of the cylinder is not flat which would not allow removal of all the diesel. On top of all these frustrating thoughts, I don't know how hard it is to remove the injectors.

Should I warm the engine every time I try to work on the remaining GPs?

Thank you.

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1998 E300 Turbodiesel 184K

With the injectors out its possible to spin the engine over on the starter, This will remove nearly all the fluid that has been put in there--What doesnt come out the injector hole will exit via the exhaust-valve........

Ally expands more than steel, so it stands to reason the plugs should be easier to remove with a warm engine...

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

http://uk.youtube.com/watch?v=koghDoROFko

That kit/procedure is for the CDI, I wish there was such a kit for our cars!

Here's an excellent write-up for our engines I bookmarked:

http://www.peachparts.com/shopforum/showpost.php?p=1707350&postcount=51

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Wow, I feel like a netspert now! My drawings are crude but I couldn't get clear pictures that explained what was going on.

I saw that when I busted my plug. I wasn't very comfortable with the idea of a slide hammer. I found these links where they make an actual puller, and that's what I did and documented in the link above

http://alan.mcreynolds.googlepages.com/howtoremovebrokenglowplugs-mercedesom606

http://www.peachparts.com/shopforum/showthread.php?t=109101&highlight=606+%22glow+plugs%22

I'll tell you this much, I have NEVER lost so much hair in one weekend. Talk about spooky.

Just the same, I would say this is not beyond the reach of the DIYer... I am certainly not particularly talented. Just be REALLY carefull with the drill. Put something long in an adjascent glow plug hole and use that as a visual guide to keep the drill at the right angle.

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Jake
1999 e300d PlantDrive WVO/SVO conversion
**note to self: oil changed at 268k kms**
1990 Toyota 4Runner FrankenDiesel swap

I didn't touch the car on Monday, so I went back to it last night (Tue).

I put the torque wrench on the hard to move glow plugs and I was amazed how much easier it was to move them. The torque wrench is also 4 times longer than my 3/8 inch wrench, so the extra leverage surely helped. I thought somehow that the carbon might have softened a bit from Sunday's work. (the setting on the torque wrench is ~48 NM)

I decided to use the 3/8 inch wrench and the GPs were very hard to turn. That is when I realized the torque wrench gave me the feeling that maybe I loosened some of that carbon.

I can see half the threads from #5 and 6 GPs. I haven't turned #3 out more than one or two revolutions. I will wait for the Kroil to arrive sometime on Friday until I try again. Its a good thing I have a Toyota Camry as my 10 yo reliable vehicle to drive while my MB is in the garage.

Can the Oil filter housing be removed so I can get easier access to the #6 GP?

Thank you.

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1998 E300 Turbodiesel 184K

when I did my 96 e300d, it took me 6 days to get all the plugs out. I used PB Blaster, and another product called Freeze-Off, which is available at almost any auto supply store. I used the torque wrench with a six sided deep socket, which allowed me to apply outward pressure to the plug while turning it. Your plugs are carbon bound, and if your are free of the threads, the carbon has a grip on the plug tips. I would squirt some Freeze-off for about 35 seconds, which lowered the plug temperature, then I would hit it with PB Blaster, and just give it a little turn back and forth. As I said, it took me 6 days to get them out, but they all came out with no breakage. Good luck!!

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96 E300d

Safety first!
I had 2 glow plugs with swollen heads ounce but on 123s they are not such a problem.
Several people have had similar problems of getting them part way out; I do not recall that there is any special trick other than to carefully keep spraying (praying) and working them. The glow plug tips may be trapped by a carbon build up.
It might be a good Idea to ream out the carbon build up from the glow plug holes ounce they are out and for sure put some sort of Never-Seez type compound on the threads of the new glow plugs when they are installed.
You might want to check some more threads for your specific problem.

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84 300D, 82 Volvo 244Gl Diesel