VAG problems. Broke...
 

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VAG problems. Broken glow plug

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The wife's Yeti is displaying an engine light and a scan revealed a faulty glow plug. It's due for a service and an MOT but the garage said that glow plugs are so prone to breaking that you have to sign a disclaimer before they do it. If you break them "It's an engine out job". Sounds scary.

So I thought I'd try to loosen them off before it goes in! Last night I successfully removed and cleaned 3 glow plugs easily but one of them was incredibly tight. When it did start moving it was very stiff and wasn't unthreading. So at least I found the dead one.

This morning the garage said there's no point in them trying to remove it if it's already spinning so now I'm looking for removal options. There's all kinds of info and YouTube videos. Specialist tool kits etc, peoples saying head off, engine out.

Has anyone dealt with one of these? Given how common Vag diesels are I thought it was worth asking. Should I be looking for a good mobile mechanic or budgeting for Armageddon?


 
Posted : 06/04/2023 9:19 am
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Was it moving at all or just spinning in the head?

If it's not moving at all then try soaking it with Plus Gas then gently trying to get it moving back and forth. I've had that work a few times with Mercedes glow plugs in the past.

If it doesn't come out/spins/snaps then it'll be a head off job to get it replaced. Not cheap but not end of the world prices.


 
Posted : 06/04/2023 9:33 am
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It's sitting in a pretty deep recess filled with penetrating fluid. I left it overnight and tried again this morning. It's definitely just spinning even though it still feels mega tight. The fluid hasn't gone down at all so I'm hoping the threads are still in tact.


 
Posted : 06/04/2023 9:57 am
 mc
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It'll need drilled out.

I've removed a few, and it's not a hard job as such, it's just there is potential for things to get very involved and very expensive very quickly.
It's a job where experience counts so you know what not to do, and when to stop.


 
Posted : 06/04/2023 10:21 am
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So I thought I’d try to loosen them off before it goes in!

The experienced professionals told you it was risky, so you had a go yourself? 🙂


 
Posted : 06/04/2023 12:51 pm
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It’s a job where experience counts so you know what not to do, and when to stop.

Sounds like that ship has already sailed!


 
Posted : 06/04/2023 2:10 pm
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I got the tool to drill them out which I was really looking forward to*

Then the engine completely shat it and I never got to use it.

*After I discovered that only one was actually intact under the lead


 
Posted : 06/04/2023 2:11 pm
 Spin
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Vag...penetrating fluid...still feels mega tight...

Go easy fella, can't hurry these things...


 
Posted : 06/04/2023 3:55 pm
dc1988 reacted
 5lab
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If 3 of them are working I'd consider just running it like that for the life of the car.


 
Posted : 06/04/2023 4:19 pm
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If 3 of them are working I’d consider just running it like that for the life of the car.

Problem being it puts a CEL on which is an MOT fail.


 
Posted : 06/04/2023 5:02 pm
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The goods news it he scanned it today, cleared the codes and the lights stayed off for the duration of the MOT so it passed with no advisories.

It still runs and drives perfectly but no doubt the light will come back on soon.

The reason I tried to do it myself is that the garage said they're so prone to breaking that they make you sign a disclaimer before they try to remove them. I knew that if I did it, I'd take my time and be very gentle. I was very careful and I didn't feel anything slip or break or do anything disastrous so fairly sure I'm not responsible for killing it. Someone at work told me I should have done it when the engine was hot but I didn't. That may or may not have helped.

I didn't have time to find anyone today. I'll try and get it sorted after the long weekend.

If 3 of them are working I’d consider just running it like that for the life of the car

I would if it was one of my sheddy old bangers but it's the wife's daily and it's a VGC Yeti Monte Carlo that might be still worth a bit of money if we look after it.


 
Posted : 06/04/2023 6:18 pm
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It's now worth a little bit less with a botched engine repair


 
Posted : 07/04/2023 8:28 am
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It’s definitely just spinning even though it still feels mega tight.

Is this where the carbon deposit on the glow plug stops it from coming out even though they unscrew? IIRC the tip then snaps off and is then squashed into the cylinder head writing the engine off?


 
Posted : 07/04/2023 9:15 am
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My Yeti's engine warning light came on yesterday so I'm following this with morbid curiosity. Not had it checked yet and although it could be a million things, I'm expecting something worrying like the glow plugs.


 
Posted : 07/04/2023 10:14 am
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the carbon deposit on the glow plug stops it from coming out even though they unscrew? IIRC the tip then snaps off

I hadn't heard of that but I guess the alternative is that the tip doesn't snap off but if you apply enough torque the thread strips? In which case the OP might do best to find a fuel additive that will dissolve the carbon, before trying further extraction.


 
Posted : 07/04/2023 8:28 pm
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When I had a stuck glow plug I took mine to Midlands Diesel Solutions. They have some special tools that means it can be removed without taking the engine out.


 
Posted : 07/04/2023 8:35 pm
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I know very little about diesel engines, but at this point I imagine the glow plug is in two halves.
If it was spinning in the threads I'd have thought you'd have leakage of high pressure fuel/gasses around the glow plug?


 
Posted : 07/04/2023 8:48 pm
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My Yeti’s engine warning light came on yesterday so I’m following this with morbid curiosity. Not had it checked yet and although it could be a million things, I’m expecting something worrying like the glow plugs

I have had glow plugs fail on both a Ford and a VW over the years. Financial Armageddon did not result from either. While clearly they can be a problem it's not a foregone conclusion that they will be.


 
Posted : 07/04/2023 8:54 pm
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I had a glow plug go on my transit connect. I think the parts were £200 and labour I don't know. Thank you extended warranty!


 
Posted : 07/04/2023 8:57 pm
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FWIW you can get glow plug removal tools that are not that expensive, they are a puller that you connect to glow plug via a hole you tap in them (the glow plug). Never used one but seen the result. Like all of these things it's up to you if it's worth the risk. Not sure what choice I would take!


 
Posted : 07/04/2023 9:06 pm
 mc
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Is this where the carbon deposit on the glow plug stops it from coming out even though they unscrew? IIRC the tip then snaps off and is then squashed into the cylinder head writing the engine off?

There are three potential issues.
The glow plug is seized into the head, which usually results in it snapping off flush.
The glow plug thread has picked up, which can result in seizing or stripping the thread and spinning.
The glow plug hasn't been sealed on to it's conical seat fully, which results in carbon building up and seizing the glow plug body into the head, which may also be combined with the above.

I've never personally had a tip snap off, but there is the potential for it to happen if you drill too far in, so it's no longer attached to the body. However if you use the correct size drill bit, the remains of the glow plug will usually spin before you get into that danger zone.
Personally, I drill them so far, then start the engine and give it a rev. However when using this approach, make sure to place a rag/towel over the glow plug, as they can release with quite some force. That some force being enough to launch the glow plug remains to come to a rest half way down the workshop having gained an additional bend in it from bouncing of something...


 
Posted : 07/04/2023 10:47 pm
 Del
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Someone at work told me I should have done it when the engine was hot but I didn’t. That may or may not have helped.

was my thought. IANAM

WBAC?


 
Posted : 07/04/2023 11:10 pm

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