Glow plugs spins but won’t come out

[sixmenn]

I recently had an intermittent glow plug indicator flashing on my dash while driving.

I decided to take them out and do a compression test, since it’s been a while. Working from left (my left, vehicle’s right) to right, I removed them one by one. When I got to the third one, it immediately spun left with no resistance. I thought, “maybe that’s my problem. One of them is loose”. But the glow plug won’t come out. The hex part spins freely, but the top stays stationary, and it will neither tighten nor loosen when I use the ratchet in it. All the other GPS came out with no issue.
Anyone have ideas???

 

[sixmenn]

Also, can I do a compression test with one of the GPs still in, or will the vehicle want to start in that cylinder alone?

 

[mittzlepick]

Not with injector pump unugged or fuel soleniod unhooked. Or injector removed

 

[454k30]

The hex portion of your GP has broken off from the rest of the assembly. Unfortunately this likely wont be easy to get out, in fact your likely to break the plug to pieces trying to get it out of there. You could try a pair of vice grips and hope the plug breaks free. You may have to intentionally break the plug off and put an extractor into the body of the GP in order break free from the head.

These engines will run on one cylinder. I've unintentionally done that! A comp test can be down via the injector hole is possible but not usual, and I'm not sure where you would find the tooling to do this.

 

[P2B]

...just by the way, there are a number of reasons for a flashing glow plug indicator (OBD will provide clues) but none of them relate to faults in the glow plug system.

 

[KLXD]

From your second post it seems like you don't routinely disable the fuel supply when doing the compression check or it wouldn't matter that your plug is stuck. Other than a dubious result on the other three.

You always disable the fueling on a Diesel while doing a compression test or the cylinder you're checking can fire. At best it would be alarming, worst case would be ruining your gauge.

 

[sixmenn]

From your second post it seems like you don't routinely disable the fuel supply when doing the compression check or it wouldn't matter that your plug is stuck. Other than a dubious result on the other three.

You always disable the fueling on a Diesel while doing a compression test or the cylinder you're checking can fire. At best it would be alarming, worst case would be ruining your gauge.

The last time I did this was 5 years ago, so I wasn’t very familiar with the process when I posted this. I’ve since looked it up and I’ll be disabling the fuel system. Thank you!

 

[sixmenn]

...just by the way, there are a number of reasons for a flashing glow plug indicator (OBD will provide clues) but none of them relate to faults in the glow plug system.

That seems strange… where can I find a list of those things?

 

[sixmenn]

The hex portion of your GP has broken off from the rest of the assembly. Unfortunately this likely wont be easy to get out, in fact your likely to break the plug to pieces trying to get it out of there. You could try a pair of vice grips and hope the plug breaks free. You may have to intentionally break the plug off and put an extractor into the body of the GP in order break free from the head.

These engines will run on one cylinder. I've unintentionally done that! A comp test can be down via the injector hole is possible but not usual, and I'm not sure where you would find the tooling to do this.

Ugh. Sounds like work….

 

[sixmenn]

Update:

I replaced the glow plugs (I didn’t do the comp test), and then sprayed soapy water on the GPs. When I started the car, there were bubbles forming around that third GP.

How do you drill the GP out and use an easy out without getting metal shavings in the cylinder?

 

[fatmobile]

I've made a T (think copper plumbing T) and used a vacuum cleaner to pull things from the side while the drill goes through the T.

 

[STDOUBT]

That seems strange… where can I find a list of those things?

Here's an at least partial list, provided by MOGolf IIRC:
00741 Brake pedal monitoring - implausible signal
01044 Control unit incorrectly coded
16705/P0321 Engine speed sensor - implausible signal
16706/P0322 Engine speed sensor - no signal
16955/P0571 Brake light switch (F) - implausible signal
17653/P1245 Needle lift sender (G80) - short to earth
17654/P1246 Needle lift sender (G80) - Implausible signal
17655/P1247 Needle lift sender (G80) - Open circuit/short to positive
17762/P1354 Modulating piston movement sender (G149) - electrical fault in current circuit
17969/P1561 Metering adjuster (N146) - control difference
17978/P1570 Engine control unit blocked
18020/P1612 Control unit incorrectly coded
18026/P1618 Glow plug relay (J52) - short to positive
18027/P1619 Glow plug relay (J52) - open circuit/short to earth
18040/P1632 Accelerator position sender - voltage supply

This is why you "need" VCDS for long term maintenance of these cars

How do you drill the GP out and use an easy out without getting metal shavings in the cylinder?

You really don't. Possibly you can cut it off under the nut portion and grab what's left but I don't know.
Any time you remove the GP's you should first treat with a penetrant like Kroil if they give you any grief.
I have read that 25 Nm is the max reverse torque you want to use on them otherwise what happened to yours, happens.
You should also test the GP's before discarding them. Using a volt meter set to Ohms, ground one lead to the engine and press the other onto the GP top tip (harness off of course). Should all be between 0.5 and 1.5 ohms and within 0.2 - 0.3 ohms of each other.
If that stuck GP tests good I would leave it alone for now. You can treat with pentrant daily for a week or so,
and try and find some way to get a grip on the threads under the nut portion.

I replaced the glow plugs (I didn’t do the comp test), and then sprayed soapy water on the GPs. When I started the car, there were bubbles forming around that third GP.

Did you clean the seats before placing the new GP's in? It's not super critical but it's nice to do.
I take 1/4" cotton rope soaked in brake cleaner and shove it down there, let soak and then rotate the cotton with a thin wooden dowel or something that won't scratch the seat, then kinda do a circular scrub of the seat.
There are torque values for a reason. GP's seated into a clean hole tighten to 15 Nm (11 ft/lbs). I also do really really thin coat of never seeze.

 

[J_dude]

I've made a T (think copper plumbing T) and used a vacuum cleaner to pull things from the side while the drill goes through the T.

I assume one would also ensure that one of the valves on the cylinder in question is open while doing this to allow air flow back through the hole?

 

[P2B]

This kit looks awesome, but I bet it is $pendy

 

[STDOUBT]

This kit looks awesome, but I bet it is $pendy

Those guys seem pretty nonchalant about the shavings around the hole....just blast that stuff with air! (1:48)
Maybe shards that small just go straight down the gullies to the pan from there? Yikes.
That kit is hella cool.

 

[fatmobile]

I assume one would also ensure that one of the valves on the cylinder in question is open while doing this to allow air flow back through the hole?

That sounds like a good idea.

 

[sixmenn]

Since my hex nut spins but the rest of the GP doesn't, if I am able to grab ahold of the GP above or below the hex part and spin it, it should come out? Or will that just likely result in breaking off the top of the GP, leaving the rest of it in the orifice?

 

[dieseldonato]

Depends on how corroded it is in the hole. Sometimes getting the electrode out and top nut off then you can grab it with an easy out, but of luck it will screw out.

 

[Tdijarhead]

That is a really awesome tool.

In case anyone is interested.

Universal diesel glow plug puller

universal tool for diesel maintenance in professional automotive and cars worshop thanks to Hubitools innovative tool experts.

www.hubitools.com

 

[csstevej]

Yeah …..I never had luck getting the broken one out of my 01 golf…. It broke off and I couldn’t grab it with anything….. luckily it did not leak.
I lived with that for almost 15 years . I connected the GP wires together so I didn’t get a CEL.
When the head gasket went I replaced the head with a used serviceable one , the pulled off head had 392,xxx miles on it.
Ran it that way for about 250,xxx miles….

 

[BobnOH]

The good news is you have not damaged the threads in the head yet. It will take some serious improvisation to get it out. Perhaps you can rent that tool, would sure help.
But I like Steve's solution, run it on 3 plugs, cross connect wire to avoid CEL. Verify plug don't leak.

 

[J_dude]

Verify plug don't leak.

I think he said it does, post #10.

 

[UhOh]

You can rent the tool (there's a person on ebay, Florida I believe, who rents them). Costly, yes, but if you botch things it'll be a LOT more costly: see my thread below. Do NOT rush this. Soak, soak and soak some more.

How did this GP get broken? They don't break on their own. Someone either over-tightened it (trying to "seal" it- note: this won't work if you have to exceed torque spec; and if doing so after a while even that won't work because you've likely gotten the seat dirty and it will not reseat).

Use ceramic paste on the body of the GP (NOT the TIP! threads don't really need it but are somewhat OK, though it'll affect torque values) and never have anything stuck.

I can assure you that things could be worse:
https://forums.tdiclub.com/index.ph...ow-to-deal-with-broken-gp-on-an-om648.525770/

All still minor league compared to stuck injectors: for real scary stuff watch some folks dealing with stuck diesel injectors.

 

[ts888]

My shop has a couple of different sets of tools for extracting glow plugs, both similar to the pictured kit. Patience is needed, but most will come out. The worst one I ever had was in a Sprinter V6, and it never came out, even after the head was off -- couldn't even pound it out from the combustion side.

 

[fatmobile]

I wonder what would happen if you tried to weld on it.
If it would heat up enough to remove easier.

 

[sixmenn]

How did this GP get broken? They don't break on their own.

No idea. When I first got the car 8 years ago, it had a glow plug issue that I resolved by testing and replacing the bad one(s). Not sure if this was one of them or not.

When I went to remove them the other day, this one was just “loose feeling” from the beginning. The others required effort to spin the GP out, but this one just spun from the get go (but didn’t come out).

I’m torn: not sure if I want to mess with it and cause myself a lot of work (and potentially introduce metal shavings into the head), or just put some epoxy on it to seal the leak, and connect the GP wires.

 

[Nuje]

Just as a point of reference: Car I was working on (BEW) had glow plug error, so I decided to check all of them just to make sure it wasn't a voltage mismatch (all three seemed to be 5V, although one of the good ones was Beru with no voltage marking, while the others were Bosch 5V - including the bad one).

Anyway, two of them had reasonable breakaway torque (20-22Nm to crack it free), while one was 7Nm, and the last one didn't even register on the electronic torque wrench (6.8Nm is the minimum reading). And absolutely no carbon or other signs of leakage around the GPs.

So - if your old GP is threaded in there to anything surpassing finger-tight, it seems that they seal just fine.