Glow plug broke in half in the hole on my A4

hey guys i have a problem, and i am afraid it is a very big one...

i was changing my glow plugs tonight and cylinder 1 and 2 went fine, but cylinder 3 broke off in the hole. it didnt take much force to do it either! but anyways its done, and now i have to deal with it.

ive deduced that the metal casing of the glow plug has broken in half right above the threads, so its still tight in there, the threads on the head have not galled, but the 10mm head on the glow plug just spins and spins.

has anyone ever come across this? im afraid the head is going to have to come off to actually get it out, but as far as i can tell taking the head off doesnt appear to be much of a problem... true?

i was trying to think of a way that i could use some sort of reverse tap, or easy out, but im not exactly sure what to do here, so i figured i would come to you experienced folk for some advice.

thanks for any suggestions

i did some tests on my old glow plugs that i took out, and heres a picture of what i think happened. i reproduced the situation by putting the threads in a vise, and twisting until it broke.



it IS possible to break the top off of it and leave me with the bottom half, but i havent done that yet on the one thats actually stuck in the engine because im not sure if it will help my case

Broken GP

Joester said:

i did some tests on my old glow plugs that i took out, and heres a picture of what i think happened. i reproduced the situation by putting the threads in a vise, and twisting until it broke.

it IS possible to break the top off of it and leave me with the bottom half, but i havent done that yet on the one thats actually stuck in the engine because im not sure if it will help my case

Click to expand...

Notice the "Taper" from the shank down to the element (top of your black line on right showing broken). Well, that taper is suppose to SEAT on a corresponding part of the head.

Who ever installed the GPs that last time did not SEAT the GP properly, thus soot/carbon build-up around the shank all the way up to the threads. That situation makes GP removal a PITA and usually ends with a broken GP as in your case.

My suggestion is to remove the head! Do not worry about setting the engine on Top Dead Center (A small piece could have already broken off and fell into the combustion chamber.). Setting the engine on TDC can be done before you go back with the head!

Others will chime in!

thanks for the suggestion, and yeah this is the first time ive had to mess with glow plugs in the time ive owned the car.

is removing the head something that i should attempt? ive cleaned the intake, taken off my turbo, and performed various other mantenance without many problems, and i do alot of work on ATV engines, in fact my 5-valve head is sitting on my workbench right now waiting to be reinstalled. the only thing that i would really be scared of is the timing belt part. ive never done a timing belt on these cars, but i would think it would be pretty easy to learn...

how in depth is head removal?

I would try the Wingnut method of busted glow plug removal before pulling the head.

Simon

Simon thank you so much! Today is the day that I try all available methods to get it out and wingnuts method is top of the list.

Pre soaking the threads with a good penetrating oil may help and some have said a warm engine to expand the hole.

Good idea, I will let it soak in PB blaster for a while before I attempt to remove it as for the warm engine idk how I would do that as the car is in pieces lol

I think I will try it cold and see how it goes.

i have successfully f**ked it up even more with my unskilled hand, so im not really sure what to do now.

first i tried the torx trick with a crappy set of cast iron torx, and that just snapped off in the hole,

so i drilled out the snapped off torx, went to auto zone and bought their most expensive set of forged/superhard/unbreakable torx, and hammered it down into the hole, and proceeded to snap that off in the hole as well.... this is one of those torx that a titanium drill bit cant even put a mark in...



so we welded a slide hammer to the little piece of broken off torx in the hole and we were able to pull the broken piece out, so we drilled it out further and used a reverse tap to try to take it out. it seemed like it was going to work up until the metal of the reverse tap itself started twisting.... so we gave up on that because that was just going to break off in the hole too...

then i went to drill the whole thing out by using a drillbit the diameter of the inside of the threads on the glow plug, but i drilled slightly off camber so once i got down far enough i started to get aluminum shavings and this is where i gave up because i odnt want to ruin it any more, it may even be too late...

i was very suprised to see that a full cylinder head with valves and cam is only like $1100 form idparts though, that seems pretty cheap for a whole head, but maybe, just maybe its not completely ruined...

further inspection reveals that i drilled pretty deep off camber into the head so i think it will require some sort of remachining process or a new head. how much does a used head go for around here? im thinking that might be the cheaper route than remachining...

update, looking at it more im 99% sure that i need to get it remachined. im going to start the head removal process, but if i get too far and im uncomfortable with it i will probably buck up and take it to oilhammer, ive messed enough stuff up already.

Take the head off...........send it to Oilhammer! It will be a 'ell of cheaper than $1,100.00!

thats the current plan, but Brain will make fun of me, lol. guess i deserve it.

I feel your pain Joester. I just went through this and it is a PITA to rectify...here is how I did it.

1) After finding the hex portion spinning without the GP coming out I snapped the electrode so I could expose the bit that was still in the head.
2) First give an extractor a try but one that is small enough to fit inside the GP won't take much torque so it'll be unlikely that you'll get it out without breaking.
3) With the head removed (actually had it off already ) I knocked the remaining portion of the electrode through the glow plug hole. Sift through your drift set and you'll find one the perfect size that will let you drive the electrode through frome the outside (to clarify the direction the electrode would fall into the cylinder if the head were still on the block).
4) So now the electrode is out and you have a perfectly centered pilot.
5) Find your drill bit that just fits in the hole vacated by the electrode. Start with the next one bigger.
6) Drop the drill bit into a GP hole that hasn't been tooefed.
7) Mark how deep the drill bit goes into the head and put some electrical tape around the bit to let you know how far you can drill into the head and NOT DRILL INTO THE SEAT. You want to drill just far enough into the body of the GP but not touch the seat. Do that and you've really messed up the head.
8) Drill into the GP body with your drill bit making sure you follow the pilot as best you can and without submerging the electrical tape into the GP.
9) Repeat steps 6-8 with increasing diameter of drill bits until the steel GP threads fall out of the aluminum.

Here's what I was left with:





When done all I had to do is run my reverse tap through the threads and voila I'm done.

For the record you run a very good chance of wrecking your head if:
1) you've drilled into the seat
2) you've drilled way off center from the GP centerline.

Post a WTB for a used head in the classifieds or talk to Frank to see what heads he has kicking around. I'm sure you can get one cheaper than $1100.

One for those who like to wring hands and scratch heads............

If the head is screwed (trash from a GP stand point), plug the hole and run it without a GP! Of course, something will have to be done to keep the ECU from kicking a CEL.........

pretty sure the head is wrecked. i definitely went a pretty far bit off center without noticing, but im not totally sure weather or not i hit the seat yet. things are dark down there and its hard to tell exactly where the seat begins... anyways, ive already sent frank a PM, a used head may be just as cheap as the machining process that it takes to fix my mistake!

also, my 2002 camshaft has some pitting, so i guess this is the time that i replace it...

You can tell from the GP picture you posted that the seat is down a full 2" into the head.

While it is probably best to send the situation off to Brian to take over, it would be a good learning experience for you to r&r the head and install the TB yourself.

yes greengeeker thats what im thinking. i definitely need to learn timing belt stuff eventually and if i can do the timing belt then the head just comes off with a few bolts right? i think i will attempt it myself and see what happens, if i realize im over my head at any point, i will just load it onto the trailer and take it to brian.

Handling the Turbo, EGR system (cooler, piping, etc.), and Intake Manifold will be the most challenging part of the job. (taking off and putting back on)

After the car is on ramps or stands (stands preferrably) and plastic skid pan removed
-disconnect the battery negative cable or both
-drain coolant
-remove the air filter assembly and hose over to the CCV area
-remove vacuum lines below the vacuum pump
-remove vacuum pump
-remove the coolant flange on the end of the head (below the vacuum pump) and tie back all the hoses
-loosen the oil feed line to the Turbo at the filter housing
-loosen the other points the oil feed line is secured
-remove the Turbo pipes (pressure and suction) from the bottom
...................at this point, you need to decide if you are going to leave the Turbo on the down pipe or remove it with the head (pretty heavy). I'd unbolt the manifold and let the Turbo flop back. The brace on the engine block has to be removed and maybe the oil drain-back line. Also, don't forget, the oil feed line is connected to the end of the manifold.
-unbolt the Intake, working from the top and bottom. I've always unbolted the EGR and associated cooler, piping, etc. It has three allen head bolts on the back side...difficult to reach, but doable!
-I always remove the Coolant Tank (thingy with the blue lid), just makes more room to work.
-I always disconnect the Power Steering reserivor, lines, etc., to make more work room......that can be a messy job with all the oil dripping, etc.(your call)
-pop off the TB cover (don't worry about Top Dead Center for #1 cylinder or the IP lock pin or the CAM plate)....do not rotate the engine. You can "set" all that stuff going back together.
-loosen the TB Tensioner and remove the TB from the Cam Sprocket, etc.
-remove the Valve Cover (could be done earlier, but due to debris, I leave it on until the last possible time to remove)
-now, begin the process of breaking loose each of the head bolts.....just break loose one and move to the next, then go back and finish (otherwords, don't just remove one completely and then another)

I'm sure I've forgot something..............

Now, make a list of parts you will need
-new head bolts
-new head gasket
-coolant
-oil change
-oil filter
??????????????/


Re-useable (your call)
-Intake gasket
-exhaust manifold gaskets (4 of them)

You may be able to remove the head by yourself, but you will need someone to help set it back on!

I'd also suggest, if it is possible, to pressure wash the engine before disassembly. Let it sit over night to dry..........makes the job much more appealing!

Of course, don't forget to clean the EGR assembly and Intake while off (that's another reason to remove it completely during the process).

This link has some pretty good photos of the ALH for reference: http://forums.tdiclub.com/showthread.php?t=276798&page=5

Also, in that Thread are other photos of the engine......maybe page 16 or 17

Hope this is encouragement and helpful too!

Same exact thing happened to me. I ended up grinding center electrode down with a Dremel tool with a diamond bit and pulling it out with a left hand drill bit.

To prevent in the future use a torque wrench to remove. I don't remember the inch-ponds but the goal is to not put too much torque taking it out. When the torque wrench trips, turn back in and try again. May take hours trying to get out...

thank you for the tips.

im not worried about intake removal. ive had the intake manifold off the car 3 times in the last 2 years. i consider that a pretty easy job.

im not worried about turbo removal except for the oil line. the oil line is somehting that i could see myself breaking no matter how careful i was.

engine is very clean, i washed it 2 times last week.

ive got about 19 tabs up on google chrome all with TDI timing belt/head removal/coolant drain/etc. tutorials up right now, but im taking calculus 3 over the summer and we are smashing a 3.5 month class into 8 weeks, so im a bit overwhelmed with that, plus i have a job, in fact i deliver pizzas, so having a car is well..... crucial to my job. right now im driving my moms 2010 civic and every time i want to pass anyone, or even speed up, im reminded how much i would rather be driving my 10 year old Golf...

and im not sure if this is something i could have helped. like i said we got a reverse tap in there and it unbent the spirals of the tap and never budged, it also broke a superhardened steel T30 torx off in there. i was putting at LEAST 50 ft*lbs of torque on it when it broke off, im not sure what else i could have really done other than try to drill it out, and thats when everything went wrong. i tried hitting the electrode out but it wouldnt budge it just smashed and bent up no matter how straight i hit it...

Well, I'd say you got a handle on it..............time seems to be your issue at the moment.

Good luck with the job!

There is a head in the shop right now that has two glow plugs that are not cooperating. When using the recommended 25 ftlbs of torque at first one would budge and one would not. After two days of soaking with KROIL, one will turn about 1.5 turns the other about .5 turns before they reach 25 ft*lbs.

Maybe we'll get them out without breaking them.

also, thank you guys for the constructive advice instead of criticizing me. im sure it would be really easy to crack a joke about my mental competence...

tear down to the head starts tomorrow....

i am going to order a new camshaft because mine has the 2002 pitting on it. do i need to replace the followers too or can i keep the ones i have? anything else i need when swapping cams? it seems pretty straight forward, i just have to make 100% sure i torque everything down right, ask me how i know.

If you get a new cam, get new lifters.

Anyone know the tap I would need to retap glow plug threads? What size and thread tap is it?