Glow plug replacement

[tdog]

I had a fault code for glow plug 4 which I finally sorted this week, without snapping the old plug!

 

I've been reading elsewhere online that it's recommended that you replace all glow plugs at the same time.

 

I can't fully see the logic of this, as 1 has failed, and now all are working again. Surely it's better to replace as they fail, so that way if your car makes it another 100k then you've got a range of glow plug ages so they won't all fail at once.

 

What's the general thinking here? Is it good to replace them all anyway for better starting/dpf regens?

Car seems happier starting now, but i did also do fuel and air filter.

[tdog]

Anyone?

[langers2k]

I did all four on my MK2 TDi. If one failed, the other 3 might not be far behind plus it wasn't much more effort to do all of them...

 

They shouldn't be needed for regens and even during start, they aren't used much on modern diesels.

 

I think it's just personal choice really

[Breezy_Pete]

Adds risk (of shearing one off for example) to change ones that aren't faulty, I wouldn't. 

[ords]

As you're told which one has failed, then just replacing the faulty one makes sense to me.

 

If you were getting a garage to do it, then having all 4 done at once would make more sense as there would be a minimum charge each time you went just to replace one glow plug.

 

 

 

[Daheee]

I need to replace number 2 glow plug but I can't even get a socket in the space 1.6TDI 2013. Any advice, it looks like I need to remove a lot of metal tubing before I can get a socket onto the plug? 

[Breezy_Pete]

Paging @Crasher for real world experience.

My take on it,  without having seen or done, would be that it's almost always quicker and easier to remove stuff that's in the way compared with struggling against poor access and/or visibility.

[tdog]

6 hours ago, Daheee said:

I need to replace number 2 glow plug but I can't even get a socket in the space 1.6TDI 2013. Any advice, it looks like I need to remove a lot of metal tubing before I can get a socket onto the plug? 

 

You need to remove the connection from that plug before you can get to the glow plug head. Is that what you mean?

 

You also need a decent socket extender and deep socket head to get the socket wrench down into the glow plug mount but this also helps with access. Mine was about a foot long.

 

I watched 2 different videos on this and they were both really helpful.

 

 

This guy's method for undoing stuck plugs worked perfectly for me.

 

https://youtu.be/BJkltDdSYV8

 

 

Edited 18 April, 2023 by tdog

[Crasher]

To honest I find them very easy.

[Breezy_Pete]

😂 never mind then.

[ApertureS]

33 minutes ago, Crasher said:

To honest I find them very easy.

They always easy! Until they're not.

 

Ive personally never had one snap or strip but good practice is to soak in penetrant, get the engine nice and hot, let it cool down again.

After this i tighten them ever so slightly till i feel them move a tiny bit

Then slowly undo using nothing bigger than a 1/4' ratchet.

 

Going back in they always get a clean of the bore, pencil wire brush to the bottom and a clean with brake cleaner then the plug itself gets a very very light coat of ceramic white grease and the glowplug gets torqued to spec.

 

The main cause of snapping/stripping is either over tightened plugs or bores that arent clean allowing carbon/soot to work its way up and bind the glowplugs into the bores.

 

 

Dont take any of this as gospel but from a time served mechanic with a good track record of snapping none so far, its my method that hasnt failed. 

(plusgas is my penetrant of choice )

[Crasher]

21 minutes ago, ApertureS said:

They always easy! Until they're not.

 

The worst are the 3.0L V6 CR TDI, the noise they make coming out is like a stuck pig! We have had a few snap and a specialist comes out and removes them.

[ApertureS]

2 hours ago, Crasher said:

 

The worst are the 3.0L V6 CR TDI, the noise they make coming out is like a stuck pig! We have had a few snap and a specialist comes out and removes them.

Ah yeah I forgot that part too.

always get to know the local glow plug/injector removal guy and have his number on speed dial.

 

good thing about the v6 tdi is the injectors like to remove themselves when the bolts snap off!

[tdog]

3 hours ago, ApertureS said:

They always easy! Until they're not.

 

Ive personally never had one snap or strip but good practice is to soak in penetrant, get the engine nice and hot, let it cool down again.

After this i tighten them ever so slightly till i feel them move a tiny bit

Then slowly undo using nothing bigger than a 1/4' ratchet.

 

Going back in they always get a clean of the bore, pencil wire brush to the bottom and a clean with brake cleaner then the plug itself gets a very very light coat of ceramic white grease and the glowplug gets torqued to spec.

 

The main cause of snapping/stripping is either over tightened plugs or bores that arent clean allowing carbon/soot to work its way up and bind the glowplugs into the bores.

 

 

Dont take any of this as gospel but from a time served mechanic with a good track record of snapping none so far, its my method that hasnt failed. 

(plusgas is my penetrant of choice )

 

 

Yeah, the tighten them up and then undo them method worked well for me. Sounded horrible but went without a hitch. That's what guy in the second video suggested and it worked a treat.

 

I don't think it's that it's hard, it's just that the chance of breaking them is reasonable and costly. 

 

[PCharm]

I'm looking to replace all 4 glow plugs on my 2.0 TDI in the coming weeks as I had the The P0671 fault code which I cleared and hasn't come back since. I suspect it will do again soon as the car is on around 120k. With that in mind do you know if it is possible to spray the penetrating oil down into the glow plugs without removing the electrical connector on top? I was going to try and get a weeks worth of running cycles in to maximise chance of success. I also wanted to confirm the torque specs are 17nm for the non-pressure sensing plugs and 12nm for the pressure sensing one?

[Daheee]

On 17/07/2023 at 14:20, PCharm said:

I'm looking to replace all 4 glow plugs on my 2.0 TDI in the coming weeks as I had the The P0671 fault code which I cleared and hasn't come back since. I suspect it will do again soon as the car is on around 120k. With that in mind do you know if it is possible to spray the penetrating oil down into the glow plugs without removing the electrical connector on top? I was going to try and get a weeks worth of running cycles in to maximise chance of success. I also wanted to confirm the torque specs are 17nm for the non-pressure sensing plugs and 12nm for the pressure sensing one?

 

Your torque specs are correct.

[PCharm]

13 hours ago, Daheee said:

 

Your torque specs are correct.

Thanks, I have been soaking them for a few days and using the tighten then undo technique all came out okay. Looking at the specs on the Bosch website it seems to suggest 10 - 15 nm for M10 glow plugs. So I'm wondering if I should use 15nm instead....

[tdog]

On 17/07/2023 at 13:20, PCharm said:

I'm looking to replace all 4 glow plugs on my 2.0 TDI in the coming weeks as I had the The P0671 fault code which I cleared and hasn't come back since. I suspect it will do again soon as the car is on around 120k. With that in mind do you know if it is possible to spray the penetrating oil down into the glow plugs without removing the electrical connector on top? I was going to try and get a weeks worth of running cycles in to maximise chance of success. I also wanted to confirm the torque specs are 17nm for the non-pressure sensing plugs and 12nm for the pressure sensing one?

 

I don't think you can spray penetrating oil into the glow plugs with the electrical connector on top, because the connectors have rubber plugs attached to them that help to protect the space from debris.

 

They are easy enough to remove with a pair of small needle nose pliers (gently!)

[PCharm]

5 minutes ago, tdog said:

 

I don't think you can spray penetrating oil into the glow plugs with the electrical connector on top, because the connectors have rubber plugs attached to them that help to protect the space from debris.

 

They are easy enough to remove with a pair of small needle nose pliers (gently!)

Thanks for the reply - I ended up taking the plugs off then hoovering/blowing all the debris out from the well they sit in. I then sprayed some PlusGas into the well and put the plugs back on. I can confirm you can in fact spray oil into them with the plugs on as I did that for the following 3 days. All glow plugs now replaced with no dramas. Hopefully good for another 100k!

[Daheee]

So I now need to replace the other 2 Glow plugs (should have done them all in one go) So the Torque setting for tightening is 17nm for normal plugs but I have one which is well stuck even after lubricating for a few days. I was wondering what the torque spec is for removal, I have gone as far as 16nm but was a bit reluctant to go any higher. Anyone know? 

[dieselV6]

Have you tried on cold engine or warm engine? Warm it up, perhaps it'll go. Much easier to remove glow plugs on fully warmed up engine block.

[Daheee]

Yes I have, followed all the procedures to the letter. Just wondering if there is any may torque to undue the old plugs?

[Breezy_Pete]

3 hours ago, Daheee said:

Yes I have, followed all the procedures to the letter. Just wondering if there is any may torque to undue the old plugs?

There's no such thing as an 'undoing torque' value in my experience. 

You will have to keep increasing  until they come out, or shear off. 

 

[dieselV6]

>>There's no such thing as an 'undoing torque' value in my experience. <<

Well, it is quoted by the manufacturer as per link below, and easy enough to conform to if you have a torque wrench that clicks both ways.

https://www.autoresource.co.uk/resources/ngk-the-process-of-glow-plug-replacement/#:~:text=To assist in avoiding glow,Fig 1%2Fmain image).

 

 

I would go no further than 35Nm for removal (M10 plug), try first 25Nm and 30Nm on a fully warmed up engine, you do not want a broken off plug.

Also note new NGK glow plugs (No 49) are marked with "10Nm - 15Nm" tightening torque on the box, so the 17Nm Skoda manual quotes might be on the high side. I tightened mine to 15Nm ~3-4 years ago on both engines,  no issues, and one of these spends 1/3rd of its life with oil cooking at 110-115deg...

 

From experience on 3 cars, I quite like NGK glow plugs, they are lighter than BERU so glow hotter, on older models (V6 BDG TDI) they would take less current but start better, and seem to last at least as long if not longer as factory fit.

Edited 3 May by dieselV6

[ords]

4 hours ago, dieselV6 said:

>>There's no such thing as an 'undoing torque' value in my experience. <<

Well, it is quoted by the manufacturer as per link below, and easy enough to conform to if you have a torque wrench that clicks both ways.

https://www.autoresource.co.uk/resources/ngk-the-process-of-glow-plug-replacement/#:~:text=To assist in avoiding glow,Fig 1%2Fmain image).

 

 

I would go no further than 35Nm for removal (M10 plug), try first 25Nm and 30Nm on a fully warmed up engine, you do not want a broken off plug.

Also note new NGK glow plugs (No 49) are marked with "10Nm - 15Nm" tightening torque on the box, so the 17Nm Skoda manual quotes might be on the high side. I tightened mine to 15Nm ~3-4 years ago on both engines,  no issues, and one of these spends 1/3rd of its life with oil cooking at 110-115deg...

 

From experience on 3 cars, I quite like NGK glow plugs, they are lighter than BERU so glow hotter, on older models (V6 BDG TDI) they would take less current but start better, and seem to last at least as long if not longer as factory fit.

If the glow plug doesn't unscrew at the max recommended torque, what are you supposed to do?