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LB7 Glow Plug Tip Broke off

33K views 45 replies 15 participants last post by  shawn macananny 
#1 ·
I had two bad glow plugs, so I bought two new ones ($46 out the door from the stealer dealer). I parked the truck, and pulled the fender splash cover things between the tire and engine. I also had to pull off the tube from the turbo to the intercooler to access one of the glow plugs. By this time, the engine wasn't hot, but hadn't cooled completely either (coolant was at/below the lowest temp on the gauge). It was still warm to the touch, but cool enough I could hold my hand on it and work without burning myself on anything.

When I pulled the first glow plug out, it appeared that the tip had broken off at some point in the past. It came out easily with a 12mm wrench and turning by hand.

Thinking this was strange, I proceeded to remove the other bad plug, which turned smoothly and easily, then suddenly made a "pop" noise and had no resistance at all. I spun it out with my fingers, and noticed it too was broken off at the tip. I looked in the glow plug hole, and as feared, the tip of the glow plug was there, somehow stuck in place.

I haven't done anything since then, since I don't know how to get the tips out. I did stuff rags in all open holes to keep out debris/animals. From reading on here and everywhere else I can find, it appears that the only real solution is to take the head off. But, since the front two glow plugs were bad (weird, huh?), I would have to take BOTH heads off! The solutions I found so far are:
  1. Spray WD-40 or some penetrating stuff in the hole, then crank the engine, theoretically shooting the tip back out. This seems to actually work on the chevy 6.2L diesel, but I don't want to risk damaging my otherwise perfectly healthy engine. What would the risk of this going badly be?
  2. Pull an injector and try and push the tip back out. Perhaps I could even grab it out. This would be better than pulling the heads, IMO, but not much.
  3. Pull the heads off and pry the glow plug tip out. I believe that if I do this, I should replace the head gaskets, which are expensive. Also, I have to do this in the parking lot outside my appartment, since I can't (well, won't) start the truck in this condition. If necessary, I will do this, since I think that buying what tools I don't have would still be cheaper than having the dealership do it.
The glow plugs were replaced less than 3 months ago, so I figured I wouldn't need to soak them or anything. I guess I may be wrong, although I suspect this couldn't have penetrated all the way up to the tip where the stick was anyway, but I am not sure. The main threads were perfectly clean (I was going to use never-seize when I put the new ones in), but came out easily (easier than loosening the nut holding the wire on).

So, what should I do to get the tips of the glow plugs out? I don't want to risk damaging my engine, and I would like to spend as little money as possible. I can use my motorcycle to get around for now, but I need my truck to be running ASAP. Any suggestions are welcome and appreciated!
 
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#2 ·
Just a warning. got a friend with a powerjoke 7.3 and he had a tip breakoff in the engine and completly destroyed that cylinder/ piston / valves. now its in a million pieces in his and my garage. BE CAREFUL. !!!!!!!!!!( now he's pulling the cup and getting new heads/ valves/ pistons etc)


one more thing the duramax is much more complicated than the older PSD
duramax=4 valves per cylinder= more work = more $$$$$$$$$$
PSD(7.3) = 2 valves per cylinder= less work = less $$$$$$$

but you get what you pay for
 
#4 · (Edited)
Just a warning. got a friend with a powerjoke 7.3 and he had a tip breakoff in the engine and completly destroyed that cylinder/ piston / valves. now its in a million pieces in his and my garage. BE CAREFUL. !!!!!!!!!!(
I am NOT going to start it until I am 100% sure that I got both tips completely out, and that there is no metal left. I don't want to ruin my Duramax, I love it too much. Thanks for the heads up!

I may try putting some solvent down the glow plug hole and rotating the engine slowly by hand, hoping that the compression will blow it out the hole. If it does fall into the cylinder, since I am rotating it slowly by hand, it won't do any damage (not that I can think of at least). If it comes out, I just saved a ton of time and money. If not, I will have to pull the head.

I don't know the clearance between the piston at TDC and the head. If the GP tip is bigger than the clearance.....ouch. Maybe a bent rod, damaged piston, etc.
You are scaring me as I know I have bad GP's just waiting to do this to me too. (Shudder)
Thank God, but the engine wasn't running when the tip broke off. I was actually just unscrewing the glow plug, and when that happened, I just stopped what I was doing. No damage has been done yet, and hopefully I can get the tip out without any problems.

I am not going to do anything for at least a day or two until I have decided the best way to approach this.

Any suggestions guys?
 
#3 ·
I don't know the clearance between the piston at TDC and the head. If the GP tip is bigger than the clearance.....ouch. Maybe a bent rod, damaged piston, etc.

You are scaring me as I know I have bad GP's just waiting to do this to me too. (Shudder)

jb
 
#5 ·
If you can still see the tips how about trying to fish it out with a thin pencil type magnet.

.
 
#8 ·
If you can still see the tips how about trying to fish it out with a thin pencil type magnet.
I tried sticking a magnet in the hole this morning, but the tip it is stuck to the head somehow. I looked in and I can't really tell what is causing it to stick (poor visibility). I am afraid to just stick a punch in there and pop it loose for fear that I may not be able to pull it out, but what choice do I have?
Go by one of those flex cables with the really strong small magnet on the end, fish it down there & see if you can loc on & pull it out. If the magnet is too big, take a dremel to it & make it smaller. I would try that first, it's cheap. If the tip is stuck in there, i don't see why you couldn't drill a small hole in it & use am ez-out or similar using a shop vac at the same time to keep the filings out of the cylinder. Short of pulling th head, that's all i got........
I don't have a drill bit long enough to reach to the end, and I would like to avoid the possibility of getting filings everywhere. I am thinking that everyone is right about just getting it loose and pulling it out with a magnet, since that is the cheapest and probably easiest way.
Spray you some "KROIL" in there. I work in the Chemical plants and deal with a lot of stuck items. That stuff works wonders..
I'll see if anyone near here sells it, because I would like to get it out. If I am lucky, it will get loose enough that a magnet will be able to suck it out without having it fall into the combustion chamber (no fishing!).

I suppose that if it does fall into the combustion chamber, I can try and get at it though an exhaust valve if I needed, or just fish through the glow plug hole.

I would like to thank everyone for the suggestions (keep em coming if you've got more) and support, and I will let everyone know as I progress.
 
#6 ·
Go by one of those flex cables with the really strong small magnet on the end, fish it down there & see if you can loc on & pull it out. If the magnet is too big, take a dremel to it & make it smaller. I would try that first, it's cheap. If the tip is stuck in there, i don't see why you couldn't drill a small hole in it & use am ez-out or similar using a shop vac at the same time to keep the filings out of the cylinder. Short of pulling th head, that's all i got........

RD
 
#7 ·
Spray you some "KROIL" in there. I work in the Chemical plants and deal with a lot of stuck items. That stuff works wonders..
 
#9 ·
Dave, we all are just glad it ain't us posting this. I have heard good things about Kroil, but haven't tried it. PB Blaster is my pick for frozen bolts & such. If it is stuck in there, you are kinda screwed because once you push it into the cylinder i don't see how to orient the thing to get it back out of a small hole. Good luck....your gonna need it..........:(

RD
 
#12 · (Edited)
2x on the PB blaster
good luck!!!
I found a cutaway picture of a Duramax (maybe a prototype, but probably similar enough for my purposes) that shows how the glow plug fits in the head. http://duramax.bizhosting.com/sema_2000/dmax_cutaway.htm

The small, black tip is what is still in the head for me, and given that it is not likely to fall in with just PB Blaster or Kroil, I think I am going to soak the snot out of it. In a day or so, I am going to turn the engine over by hand (with a wrench probably) and see if the compression will be enough to shoot it out the hole. If so, I just saved myself hundreds of dollars in gaskets and uncounted hours of labor. If not, no harm, and back to square 1.

Thanks for the well-wishing & continued ideas, and I'll keep everyone posted.

go to home depot they have a camera for sewer lines that might fit,just an idea?
If I end up dropping the tip into the combustion chamber, I'll see if I can get one (or a borescope) to help me extract it, but let's just hope I don't end up with the tip in the cylinder!
 
#13 ·
might be a dumb idea but why not try some 60 second epoxy on the tip of a metal rod or something and stick it to the tip. I guess you could risk getting epoxy in the bore too though. I guess there's no way to pressurize the cylinder through the injector hole is there?
 
#15 · (Edited)
I thought of the 60-second epoxy thing, but decided not to for the reason you stated (worried I might get some on the bore). I could pressurize the cylinder through the injector hole, but the would involve pulling the injector. :eek:
The compression thing might work so long as its not on the down stroke and suck it in right? Another option would sound dumb but use a heavy vacuum (like say a long vacuum line going to a car engine revved up with an inline filter/screen) and rig it to a fittitng that would seal to the glow plug bore (like the rubber fitting from a cheepo blow off tool).
I figured that the vacuum that would be present in the cylinder without the engine running would be minimal, since the intake valve would take care of the intake stroke, and the power stroke shouldn't see much vacuum (I would imagine), since it is just returning the compressed air back to atmospheric pressure. Unless it was on compression and leaked down, then there might be some vacuum.

I like your vacuum idea, so what I might do is after it is soaked for a day or so, put a vacuum on the outside, then start turning the engine over. That way, there will be a vacuum on both sides for a little bit, but then it will start compressing, and will have pressure on the inside and a vacuum on the outside. This sounds like the safest idea so far. Thanks!

Any other thoughts people?
 
#14 ·
The compression thing might work so long as its not on the down stroke and suck it in right? Another option would sound dumb but use a heavy vacuum (like say a long vacuum line going to a car engine revved up with an inline filter/screen) and rig it to a fittitng that would seal to the glow plug bore (like the rubber fitting from a cheepo blow off tool).
 
#16 ·
http://cgi.ebay.com/RUBBER-TIP-AIR-...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50

One like that. You can get them at wal-mart for $4 Thread a 1/4" male disconnect in there (wal-mart/lowes $1) get like 20ft of 3/8" vac line ($20 from autozone then return it), slip and clamp that over the male disconnect, put a 3/8" carb fuel filter inline ($3 from autozone), hook that to the brake booster connection on the donor cars engine (you wont need power brakes right now anyway) then start the doner car (the valve will keep the engine from dying), have someone rev it to about 2k, seal your rubber tip on the hole and press open the valve you would use to blow, but it will now suck. I would think 20hg would pull anything out of there. Would be a less than $30 attemp plus you could just return the 3/8" line.
 
#18 ·
press open the valve you would use to blow, but it will now suck. I would think 20hg would pull anything out of there.
Yeah soaking sounds like a good idea. If it was just one broke off i wouldnt be too concerened with the piston being on a power stroke but you have two broken right? You're right that would be your best bet but would require 3 people or 2 if you just let the donor car idle although you would have to rig two fittings for the two cylidners.
I have most of the parts I need, but I only have 1 air gun thing, so I will have to pick up a 2nd one. One filter should do it, and a few bucks in hose. I can get a couple of my friends over on Friday to help me out, and see if we can't get this thing fixed. I'll be praying that this will work!
 
#17 · (Edited)
Yeah soaking sounds like a good idea. If it was just one broke off i wouldnt be too concerened with the piston being on a power stroke but you have two broken right? I would think on the power stroke (intake and exhaust closed) if the engine had good rings it would even create a slight internal vacuum. The idea of creating a vacuum on the outside would be ideal as you turn it over. You're right that would be your best bet but would require 3 people or 2 if you just let the donor car idle although you would have to rig two fittings for the two cylidners.
 
#19 ·
Its the next best thing i can think of asside from pulling the heads haha. Get a metal fuel filter if you can just incase for some reason the plastic one collapses under vacuum which im not sure why it would. The filter element shouldnt be affect since you're creating a small volume vacuum but if a plastic filter were to collapse from vacuum i could see maybe some plastic pieces getting in the engine. I dont see 20hg doing that though.
 
#20 ·
You will probably also need a shop vac or something too to get the tip out if it frees up since it wont fit through the blow gun tip and if its plastic it wont be magnetic.
 
#21 ·
The tip of the glow plug is metal around ceramic (from what's left on the main body I pulled out), and is magnetic (slightly), or at least the new one is.
 
#22 ·
#23 ·
Man good luck!
Kroil is the bomb, their website says 2 cans to the door for $12 or it did.
 
#24 ·
If you do get it out, you might be the first, and youll have to write up a how to in the DIY section. :rolleyes:

However, I am not holding my breath! Mine were replaced once at the dealer with no issues. I don't know that I will attempt it myself. At least if the dealer breaks it off, I can argue it's there fault! :D
 
#26 ·
Well i'm doing my headgaskets this weekend so if i break any off i'll let you know how hard they are to get out of the heads haha.
 
#27 ·
Not wanting to freak you out but if the tip broke off and is stuck in its bore there is a big possibility that the tip has been overheated and expanded. This is likely the reason it broke off in the head. If this is the case you are gonna have to pull the heads which is not as bad as it seems, I've done head gaskets and injector cups on a friends truck. If you have to pull the heads remember the head bolts have to be replaced also.
 
#28 ·
Kroil is better than PB Blaster. But the stuff from GM is better than Kroil. I think it's called Heat Pipe Lubricant. It is both a penetrant and a rust dissolver. It's like 10 bucks for a 12oz spray can from the GM dealer.

jb
 
#35 · (Edited)
2x on Kroil it actually illegal in many states!

In reading about getting broke glow tips out, there were several that the dealer drilled them out and re-threaded the head. I would try that with a long bit.

This may be a stupid thought, but can you have the engine running when you drill it out so that it will blow the bits out once you break thru like you do when drilling an EGR probe?

jb
That exactly what I would be doing because there is physical no way it could fall in to the engine with the engine running. There no way I would spend 30 hours pulling heads off.... Drive it till it shoots out!
 
#30 ·
Status update: I tried vacuuming the tip out as described earlier to no avail. Even after soaking them with PB blaster (I didn't order the Kroil, as the stores had PB blaster in stock), they didn't vacuum out.

After trying to vacuum them out, I tried just that. I put a vacuum on the outside of both of them and rotated the engine over a few times, then fired it up. It started just fine even with the glow plugs disconnected, go figure. I let it idle for 2-3 minutes, and nothing. I am afraid to go drive and get on it because I wouldn't be able to tell when it came out, and could jack up the engine. I probably didn't let it idle long enough, but I chickened out. I don't actually think it could hurt to let it idle as long as I have people watching to see if they come out, so I might try it again today.
If you do get it out, you might be the first, and youll have to write up a how to in the DIY section. :rolleyes:
However, I am not holding my breath! Mine were replaced once at the dealer with no issues. I don't know that I will attempt it myself. At least if the dealer breaks it off, I can argue it's there fault! :D
I am going to have them done at the dealer from now on, this is ridiculous.
how about mix up some jb weld stick to long skinny rod and set on tip wait till it dry's and pull up slowly.just a thought
I managed to get a drill bit to bite in pretty good to one of them, but it still wouldn't come out. That thing is STUCK! I think that since it broke the original casing, JB weld wouldn't help much, as it would just brake the casing off a little more, leaving the rest in there still.
Well i'm doing my headgaskets this weekend so if i break any off i'll let you know how hard they are to get out of the heads haha.
I hope I don't end up doing this, but if you could send me pics of the glow plug holes from the INSIDE of the head, I would appreciate it. Actually pictures of the teardown would be awesome too.
Not wanting to freak you out but if the tip broke off and is stuck in its bore there is a big possibility that the tip has been overheated and expanded. This is likely the reason it broke off in the head. If this is the case you are gonna have to pull the heads which is not as bad as it seems, I've done head gaskets and injector cups on a friends truck. If you have to pull the heads remember the head bolts have to be replaced also.
It's not looking like I have much of a choice besides pulling the heads. :mad:
Kroil is better than PB Blaster. But the stuff from GM is better than Kroil. I think it's called Heat Pipe Lubricant. It is both a penetrant and a rust dissolver. It's like 10 bucks for a 12oz spray can from the GM dealer.
I'd never heard of it, but I'll have to check it out.
 
#31 ·
MOst things I've read say you end up pulling heads to remove broken glow plugs. Man I feel for you. If you see head removal coming and you do it yourself you will need a few select tools to make the tear down a hole lot simpler. 19mm flarenut crowfoot, a 5mm 1/4 drive swivel allen, a 5mm straight allen(buy good quality allens), a compressor/blow gun with a long tip on it,... nothing else comes to mind at the moment but I'm sure there is something.

Good luck.
 
#32 ·
Thanks. I tried for 3-4 hours today to get the tips of the glow plugs to come loose, but they are stuck to the heads. I am probably going to pull the heads over Spring Break at my Dad's shop, where we should have all the needed tools. Thanks for the list of special tools, I'll make sure he has them all before I show up.

For now I guess it's just save up for the parts I will need (gaskets, head bolts, etc.) and ride my motorcycle when I need to get anywhere.
 
#34 ·
In reading about getting broke glow tips out, there were several that the dealer drilled them out and re-threaded the head. I would try that with a long bit.

This may be a stupid thought, but can you have the engine running when you drill it out so that it will blow the bits out once you break thru like you do when drilling an EGR probe?

jb
 
#39 · (Edited)
In reading about getting broke glow tips out, there were several that the dealer drilled them out and re-threaded the head. I would try that with a long bit.

This may be a stupid thought, but can you have the engine running when you drill it out so that it will blow the bits out once you break thru like you do when drilling an EGR probe?

jb
If someone knows the glow plug is a softer material than the head, this might work. However, I'd think (I don't actually know) the diesel cylinder pressures enountered with the engine running would be extremely dangerous if someone was in line with that glow plug hole when full engine running pressure comes shooting out with pieces of metal. I klnow about this method with gasoline engines, but these diesels are in a whole different category with respect to this method.

I'd be more likely to use this method but with someone hand cranking the engine to provide a positive cylinder pressure to slow it's force down, if a person can even manually turn these engines.

Or maybe: You know how long the glow plug is so drill until you have about 1/2 to 1/4" left and start the truck (making absolute certainty no one is in the line of the hole to get hit). It may be enough to loosen it to shoot out. If not, drill another 1/16" and try again. Keep taking metal until it shoots out before the drill makes it all the way to the end to keep everything out of the cylinder.

My big unknown hesitation to this method but worthy of consideration is: what would be the ramifications of scoring the glow plug hole as you drill? Not the threads because I'd think you could protect them with soda can aluminum foil wrapped around the drill bit to keep it centered and off the threads, but rather the scoring of the hole down around the glow plug element. If really nothing and it is certain the glow plug element is a software material than the cylinder head, I'd see legitimacy in this approach.

my 2 cents of thinking out loud wondering how I'd creatively attack this if faced with it.

Andy

On edit: hmmmm.... if I recall the picture of a glow plug, one might be able to wrap an alunimum sleave around the drill bit far enough that it protects as much of the glow plug hole all the way down to the smaller glow plug tip. This would help minimize scoring and help center the bit on the element. In the typical hardware store/ builder supply store, don't they have such thin wall metal tubing in their "metal/angle iron racks??? I'd go with the thinnest wall stuff I could to reduce as much glow plug element pressure. hmmmmm....
 
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