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Glow plug wont come out

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glow plug
6K views 25 replies 6 participants last post by  madnoel10 
#1 ·
I have a 2003 Laguna 1.9 dci Inititale. The garage wanted to remove a faulty Glow Plug but they couldn't remove it. They said that as its ceramic at the bottom it could shatter leading to more work - and at Renualts prices this could mean a remortgage!

Does anyone have any ideas how we can take out the Glow Plug safely?

Also, where has the thread gone about Laguna engine not starting when its hot? I have the same problem. The thread apparantly has moved - but where too?

Matt
 
#2 ·
Hi i would try to take the plug out when the car is hot this may made it just that little easyer to remove and spray it with WD40 and leave to site for awhile i hope this helps.

The forum as been through a few changes in the last week and some parts are know Subscripion only this is where it has maybe moved to but iam not sure i hope this helps all the best Donald
 
#3 ·
I'd agree with Donald, try removal with the engine hot.

Also I'd get confirmation that the base of the glow plug is in fact ceramic.

I know things could be wildly different, but I'm looking now at a glowwy that came out of my old 2.2 RTDT Lag 1

PN on the box 77 00 861 906
GN 905

It certainly doesn't consist of any ceramics.
 
#5 ·
If the ceramic part breaks off,then it's a head off job to get it out!:(

The end of the plug expands and gets stuck in it's mounting hole,so as you undo the plug the tip breaks off........
lagdti Which bit of it is ceramic bit.

The one I'm looking at is used, but still kicking. The only bit that I can see that could possibly be ceramic is the electrode, but since this is only about half the diameter of the thread, I can't figure out how it gets stuck. :confused:
 
#7 ·
Thanx mag1 yes that is one, it looks just like the one I have here. I'm assuming now that the ceramic bit must be the electrode on the right hand side of this picture, but I can't figure out why this should break off, it looks so narrow compared to the the rest of it.
How could the electrode, if that is the ceramic bit, snag or bind? :confused:

 
G
#8 ·
Never having done one and looking at the picture you have posted and comparing it to the one I posted

It steps down three times after the threaded bit.
AND ONLY TWICE ON YOUR PICTURE.

It would seem that the electrode has burnt away.

I will try to find some more clearer pictures.
 
#9 ·
I must admit,I'm not sure if the end is ceramic,but the tip is the part I was talking about!:eek:

The tip fits into a small hole which is a reasonably snug fit,but as the plugs get used the tip swells(oo-er missus!),and consequently when you undo the plug,the end snaps off and stays in the head.I've had it a couple of times,but have never had to remove a head as the customer has asked for the broken plug to be re-fitted and they've gone on their merry way.Common rail diesels rarely need the plugs to start in 99% of conditions,so one dead one doesn't make too much difference.

I had a plug snap on an HDi Peugeot engine and actually ran the engine with just the tip in the head hoping it would pop out,but it didn't budge and the car is still running around now with only 3 good plugs in it.I see it quite regularly and the customer has never had any problems with poor starting.:)
 
#13 · (Edited)
Stuck Glow plug

The tip or heating end of the glow plug isn't made from ceramics - it is either platinium or iridium which can transmit heat from it's internal heating element yet be able to withstand the effects of combustion and all the chemicals involved. They can be quite soft depending on their age. I have seen probs with seized glowpugs and if forced they break just below the hexagon nut section. (see below) The old Ford Escorts suffered the same problem with their spark plugs as both the ford plug and the glow plug are seated on a taper face which can become difficult to undo. :)
 
#16 ·
I think we’re almost all getting confused now. ;)
mag 1 I haven’t got a problem with my glowies yet, well I hope I haven't.

The pici I took was of a glowie that came out of my old Lag1 TBH, these are the only out of car glowies that I’ve ever actually seen.

I know compared to loads of other posters I have a lack of knowledge, but after reading about the ceramic and looking at my glowie I was concerned about the alleged ceramic bit referred to from mattdud post click here

BTW I know there isn't a solution to mattdud problem yet, but nevertheless, great posting folks. :)

madnoel10 thanx for the information on either platinum or iridium. Can someone please explain WTF the ceramic bit comes in? My concern was that maybe mattdud was being misled by the garage.
 
G
#17 · (Edited)
Nice to know that your not having problems

Everyone was trying to help you and that's nice
I've no problems with any post

What a great bunch hey!!!!!

I have personally stripped many two and four stroke engines
FROM MOTORBIKES,CARS,BOATS, BUT NEVER DIESELS

Though I have read many parts books on diesels.

nice to know so many care.
 
#19 ·
Nice to know that your not having problems

Everyone was trying to help you and that's nice
I've no problems with any post

What a great bunch hey!!!!!

I have personally stripped many two and four stroke engines
FROM MOTORBIKES,CARS,BOATS, BUT NEVER DIESELS

Though I have read many parts books on diesels.

nice to know so many care.
Well said, and I agree mag1, I wanted to leave you some rep points but the forum say's I got to spread some elsewhere first. :crazy:
 
#18 ·
Hi again you said the garage could not remove it, have you tryed yourself, i do not wish to scare you but if you try and it moves and comes out easy!!!!its just a guess but i wonder if it broke with them and they have just screwed it back up for you to deal with it. I hope this is not the case but if you are unable to get it out i would just go to Renault and let them deal with the problem i hope you get it sorted out keep us all posted on this cheers Donald
 
#21 · (Edited)
My Glow plug won't come out

I can understand the garages reluctance to remove it as if it breaks whilst they are doing it they become liable. I have heard of glow-plugs breaking when trying to be removed but as I said earlier they usually break just below the hexagon bit - the metal bit rings off. When this happens it usually means a cylinder head off job. Because they have a tapered seat (no washer like a standard spark plug) they will get a very tight grip - this can be due to overtightening as the recommended torque is quite low (20Nm or 15lbf/ft). Before going any further I would double check to see if it is working by testing it's resistance compared to a new one. If it's duff and must come out I would try to be very patient and soak it for a number of days with diesel (WD isn't a very good releasing agent). Soak it whilst cold - drive it till it's hot - soak it again - repeat this numerous times. Use either a six sided ring spanner or socket and apply gentle pressure whils the engine is hot. As the cylinder head is alloy and the plug is steel the alloy should expand more than the steel. Theoretically this is the best time to do it - but even this has the risk of breakage so be prepared for the worst. It may be worth asking the advice of diesel specialist who works with diesels day in day out.:)
 
#23 ·
Glow Plugs

Hi - Had a good look around the internet and yeh there are ceramic tipped glow plugs available but it is not ceramic as we know it (not the same as white part on spark plugs which is very resistant to heat) - it appears these are fairly recent and tend to be used in some of the latest high-performance diesel engines (some new Toyotas). The ceramic in these glow plugs is made from silicon nitrite which whilst very resistant to heat and shock is also good at transmitting heat. They are designed to allow quicker starting and longer life (one manufacturer claims they will outlast the engine). But the cost is up to 6 times more than the convential glow plug. Additionally they require a different control system. But again their appearance is similar to those shown on the posts and I don't see how the ceramic bit would break when being removed.:)
 
#24 ·
I'm in a similar position. Vehicle is a 200,000 mile 1.9 dCi Trafic. Garage says that diagnostics are indicating imminent failure of two glow plugs, but they don't want to try to take them out as they've had previous problems. Says he expects Carbon buildup on the tip will stop it coming out the hole in one piece. If this is the case and it needs the head off, I'm probably cheaper to look at replacement engine. Don't want to do this, so does anyone have any suggestions to get the damn things out without breaking them? Thanks in anticipation
 
#25 ·
I don't know it you've already tried this but if you feel the engine is going to be scrap anyway, I'd be inclined to try to remove it while engine is fully up to temperature, if you can get it turning I recommend you don't just carry on turning all the way, once it starts moving soak it with a penetrating type of fluid, me I prolly go for WD40 although there may be a better product.

Heat is amazing, at removing tight bits.
 
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