Glow plugs Disaster!

Google44

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I have recently replaced 5 glow plugs on my ML270. The first one failed immediately blowing up the relay. Anyway, I’ve fixed the relay but the came out easy without the glow bit at the end!

I have tried to start the engine hoping compression will blow it up, I put oil on it hoping it will give in but nothing. How come that compression is not taking it out. The metal part of the plug is out – just the bottom glow bit is in. Cannot understand what is holding it. Is this directly looking in cylinder?


Somebody advice me to use EASY OUT drills to extract it. Need advice. Otherwise, I know that last option would be head off.
 

Xtractorfan

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I would suggest you get someone from an engineering firm to look at it..other method is to drive away and keet the bonnet closed..when the engine is running.. and it will blow itself out.. The reason the compression doesnt immediately blow it out is possibly the threaded piece is still in
 

Parrot of Doom

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Don't try and drill it out yourself, you probably won't get it perfectly straight and you'll end up drilling into an oilway or something.

As above, get an engineer to look it over. Mercedes dealers have a toolkit for removing stuck glowplugs.
 
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Google44

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thanks...will try MB tomorrow. There is no thread defo left in. The cote came out complete. compresson is not getting out as I put lots of oil and is still on it.
 

LYNALL

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Mate had this years ago i told him to stuff some rag over the old plug, so when it blew it wouldnt damage the bonnet and just drive it until it eventually blows out, took a few days to come out.



Lynall
 
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Google44

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The trouble is - I am driving on holiday in Europe on Friday.

This is what I am goint to do. I will drive it as it is. If it comes out - got socket and new plug ready. If it does not - will deal with it when I come back from holiday. If it comes out partialy e.i loosing compression but not out - got the top of the plug blocked off and ready to cover the hole. Also taking road side cover in europe.

will try to find something to cover over it. Dont know if rug is OK because of heat there. Should be ok - I guess

Hope all goes OK.
 

kebo57

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If it comes out partialy e.i loosing compression but not out - got the top of the plug blocked off and ready to cover the hole.
will try to find something to cover over it. Dont know if rug is OK because of heat there.
Hi regarding blocking off
if you have the old plug / damaged plug then you could shorten it buy sawing it off just below the threads then screw it back in, if you haven't then you would need a 10mm dia X 1.0mm pich bolt to do the same thing with

Kevin
 
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Google44

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I do have the old plug. At the moment, I prefer to leave it open so it gets blowed out. I will block it only if it starts loosing compression but does not blow it out.
 

exeng

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I know of a vito van with this problem it has 18k since it happened to him and its still there but i also heard of a guy that drove up motorway and after a couple of mile out it came just proves the point that its not the thread that causes them to stick
 
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Google44

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quick update to above...

Done nearly 5 K miles most on motorways to meds and back from UK. The glow plug still in.
 

exeng

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chances are it in to stay but you could try a product called triflow it the best penetrating lube on the market fill the hole and go for a drive or even let it tick over until red hot,as i have said on several posts it is not normally the thread that causes the problem.
have you got a picture of what came out
 
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Google44

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Thanks for reply. I dont have the picture but it is just the bottom glow part. The long metal bit along with thread came out ok.

Can you advice where to get triflow?
 
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Alex Crow

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this is an unusual problem! presumably the glow tip is siezed in with carbon? if so soak overnight with carb cleaner and run engine next day.
 
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Google44

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OK. I had break oil on it but did not help. Did try WD40 over night too. Next will try is penetrating oil. Like I said the glow bit at the bottom is the only bit left in. When I was abroad local garage suggested that this is a common fault and they usualy take it out by slow dril dipped in fat so it collect metal bits coming off.
 

panason1c

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quick update to above...

Done nearly 5 K miles most on motorways to meds and back from UK. The glow plug still in.


After doing 5k miles and the plug is still in i cannot for the life of me see any penetrating oil having any effect whatsoever, the plug is well and truly stuck!....probably the tip has 'blown' and expanded causing it to be well and truly wedged...........you need to visit a good engineering shop with experience of this kind of problem to remove it............
 

kebo57

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Hi I have sectioned a ml 270 heater plug see pic
Might be possible to tap the remainder of the plug out to 4.5mm make a 4.5mm slide hammer try pulling it but its going to need some tooling guide bushing to suite everything that going down the hole
flat bottom what's left so nothing going to wander
center drill
then drill 3.5mm dia for about 10mm this should follow whats there
then tap 4.5mm
thread a shaft 4.5mm X 15mm length with slide hammer arrangement on the other end, then just keep lightly tugging at it.
 

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Google44

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Thanks for the pic and advice. I did buy thread drils before thinking of doing it. i was wondering if I could drill out the heat isolator in the middle only and try with a long nut of 3.5+ mm to thread in. Cannot use the threaded drils as they are not very long. I know I have to be very carefull will low speed drill. Looking at the old glow plug it looks like only the very small part of it sits in the chember and it is shaped so it cannot drop in.
 

panason1c

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Thanks for the pic and advice. I did buy thread drils before thinking of doing it. i was wondering if I could drill out the heat isolator in the middle only and try with a long nut of 3.5+ mm to thread in. Cannot use the threaded drils as they are not very long. I know I have to be very carefull will low speed drill. Looking at the old glow plug it looks like only the very small part of it sits in the chember and it is shaped so it cannot drop in.


Try only drilling out the middle but then carry on driving the car, with the middle drilled out it should loosen more easily under engine compression. Less chance of damaging anything this way.
 
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kebo57

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Thanks for the pic and advice. I did buy thread drils before thinking of doing it. i was wondering if I could drill out the heat isolator in the middle only and try with a long nut of 3.5+ mm to thread in. Cannot use the threaded drils as they are not very long. I know I have to be very carefull will low speed drill. Looking at the old glow plug it looks like only the very small part of it sits in the chember and it is shaped so it cannot drop in.
I'd like to see this first hand where is you rough location
You could drill it all away, starting with 2.0mm dia then work up say in 0.5mm incroments all the way up to 5.0mm so there is only small pieces of swarf for the engine exaust system to deal with.

Kevin
 
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Alex Crow

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i say again, this is an unusual fault. i have drilled out many sheared glow plugs on 604, 605, 606, 611, 612 and 613 engines but usually after they have sheared immediately below the hex (careless coleagues!). for just the tip to sieze is very unusual and possibly due, as someone said, to the tip blowing and expanding - if so forget it, put a bolt or the old piece back in and forget it, cdi's don't need much glow to start anyway.
 


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