13 minutes ago, ords said:

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

 

Apply heat, penetrating oil etc and hope it comes out...

 

If not, add more torque until it either comes out or snaps. Once it snaps, drill out and heli-coil it 

5 hours ago, langers2k said:

 

Apply heat, penetrating oil etc and hope it comes out...

 

If not, add more torque until it either comes out or snaps. Once it snaps, drill out and heli-coil it 

Exactly. Seems a ridiculous guidance to me. 

On a previous car (Mk1 Superb), I had 1 problematic glow plug. I tried undoing it to the torque limit, wouldn't budge. So I drove for another week with some motor oil around the glow plug. Afterwards I tried again to the limit, the glow plug came out without much protest.

Had I not  known the limit, I'd have snapped the plug on the first attempt. I'd say knowing the torque limit was useful to me, 

YMMV, but please note not everyone works on workshop timescales, a lot of us are fixing our own cars... on our own time/dime

 

 

Ty for the replies. I will put more oil round it and give it a few more days. I am using Bosch plugs so might go 2nm over the 17nm tightening spec next time I try. Will let you know either way.

I suspect you will have to get much more brave.

1 hour ago, Daheee said:

Ty for the replies. I will put more oil round it and give it a few more days. I am using Bosch plugs so might go 2nm over the 17nm tightening spec next time I try. Will let you know either way.

 

1 hour ago, Breezy_Pete said:

I suspect you will have to get much more brave.

 

Even subtracting further 5Nm from the lower value to be safe for caution, you should be OK with 30Nm torque for undoing, these are M10 plugs. Also, even if it does not appear to move, if the glow plug is surrounded with oil, applying some sensible torque might allow oil to penetrate deeper in the thread

I've had good luck using a small impact wrench/driver, keep it on a low enough setting so it just sits there and gives it a good rattling to free things up. The vibrations might help

It surely does, I have had amazing results with my Bosch 18v 1/2" drive one (not a small wrench) on completeky rusted trailer fasteners that I never had before when using an air dugga-dugga.

On 10/03/2023 at 07:16, tdog said:

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.

Hi tdog,

I have the same fault code for glow plug cylinder 4.

I'm only replacing the 1 plug. Can you remember if 4 was just a regular glow plug, or the more expensive pressure sensing plug?

From what I've read online there are 3 regular and 1 pressure sensing.

If you're replacing them yourself, there is no labour cost involved. If you get a garage to do it, then you're going to be hit with a labour charge every time, so it would be cheaper to replace all four at the same time.

15 hours ago, ords said:

If you're replacing them yourself, there is no labour cost involved. If you get a garage to do it, then you're going to be hit with a labour charge every time, so it would be cheaper to replace all four at the same time.

Mechanic said he'll only replace one due to the risk of doing 4 and 1 of them snapping

15 hours ago, smokinmonkey said:

Mechanic said he'll only replace one due to the risk of doing 4 and 1 of them snapping

Mechanic is being lazy and hasn't heard of penitrating oil aka WD40.

On 09/04/2025 at 00:03, smokinmonkey said:

Hi tdog,

I have the same fault code for glow plug cylinder 4.

I'm only replacing the 1 plug. Can you remember if 4 was just a regular glow plug, or the more expensive pressure sensing plug?

From what I've read online there are 3 regular and 1 pressure sensing.

Yes number 3 plug is the pressure sensor, the others are normal glow plugs.

Hi all, how do I find out if my Octavia has a pressure sensor in or not as Skoda took my reg and he said that he can't see it with a pressure sensor , this was the same at gsf parts

Skoda Octavia vRS MK3 2014 2ltr 181 bhp

1 hour ago, Holderness88 said:

Hi all, how do I find out if my Octavia has a pressure sensor in or not as Skoda took my reg and he said that he can't see it with a pressure sensor , this was the same at gsf parts

Skoda Octavia vRS MK3 2014 2ltr 181 bhp

Open the bonnet, pull off the plastic engine cover, then watch the start of this: https://youtu.be/i2AEvaPXzn8?si=0J1heJ7Nn9op-Q71&t=80

Pressure sensing plug is the 3rd one over, it will have extra wires running to it

Going to attempt this myself this week, codes show that plug 4 is throwing an error. I have a low torque wrench, so figure it should be safe enough.

Plan is to squirt some plus gas in, then let the engine warm up while I drive over to ECP to collect the glowplug. Then hopefully it'll be easy enough.

NGK plugs say they don't need any anti seize compound, so in theory it should be as simple as:

Unscrew old plug

Clean internal threads with wire brush

Hand tighten new plug

Torque to spec

Right?

15 minutes ago, ApertureAndy said:

Going to attempt this myself this week, codes show that plug 4 is throwing an error. I have a low torque wrench, so figure it should be safe enough.

Plan is to squirt some plus gas in, then let the engine warm up while I drive over to ECP to collect the glowplug. Then hopefully it'll be easy enough.

NGK plugs say they don't need any anti seize compound, so in theory it should be as simple as:

Unscrew old plug

Clean internal threads with wire brush

Hand tighten new plug

Torque to spec

Right?

I did mine myself and 1 extra step before you remove the plug.. Get some kitchen roll and a long screwdriver or something pokey and clean around the plug / absorb all the extra plusgas before removing. There was a good bit of grime and I'm pretty sure you don't want that flying in once you remove the plug.

22 hours ago, smokinmonkey said:

I did mine myself and 1 extra step before you remove the plug.. Get some kitchen roll and a long screwdriver or something pokey and clean around the plug / absorb all the extra plusgas before removing. There was a good bit of grime and I'm pretty sure you don't want that flying in once you remove the plug.

Good point!

Looks like it's a job for Monday so will see how it goes, also have to replace the heater matrix 🤦‍♂️

I do not agree they are serviceable wear items. There are two conditions, working or not. Replace one at a time.

I have heard of multiple garages refusing to replace 1 glow plug and insisting to do the whole set which is a problem if they are throwing a £130/glow plug at your car for no reason.

Soaked it in plusgas for a couple of days, got it up to temp and it came out with no fuss at all thankfully! So all sorted.

Replaced all four on my '2016 Octy 3 'at 194k km last week (error was on 3d expensive plug, with press.sensor).
All unscrewed nice, on hot engine, without soaking in penetrating fluid (torque wrench doesn't clicked even on 20Nm). From factory, 3 were Bosch and 1 was Beru.

There was doubt about tightening but ended-up with factory recommendation 17Nm (simple plug) and 12Nm (press.sensor plug) / dry.

All four new are Beru now and they recommend use ceramic grease and 15...20Nm for both types of those M10x1 plugs.

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How correctly dismantle 3d electrical plug without risk to damage it?

This question remains open. I opened fixing plastic tabs with 2 hooks.