Glow plug removal and replace

[seatalehandro]

Figured I would just bump this topic instead of making a new one.
2003 Alhambra, 1.9tdi (AUY, 85kW). Seems I need to replace the ignition glow plugs.
Is there anything particularly tricky about this job or are there any special tools required?
I know that, if I am unlucky, they will be impossible to remove and I will have to get the car to a mechanic, but apart from that - easy job?

Thanks in advance.

[johnnyroper]

Easy to access but could well be seized in.
Spray some plus gas around them for a few days before changing.
On day of change get engine warm and use a 1/4 drive socket set you will need a deep 10mm socket and extension. Crack off plug and wind out slowly if tight go 1/4 turn out 1/4 turn back in and gradually increase amount you go out until they free off.

[insanitybeard]

Is there a particular reason you need to replace the glow plugs such as struggling to start from cold? They are more necessary with these engines to aid cold starting at this time of the year with the colder temperatures. I tackled this job on mine earlier in the year- as johnny says, probably worth spraying them with penetrating oil a few days prior to trying to remove them. I'm pretty sure mine were all original and had never been out before I attempted it- 3 out of 4 came out no problem and the last one was a disaster- tight all the way out (despite trying to gradually back it off and wind it back in) and when it finally came out the thread on the glow plug was mashed as can be seen below. Pretty sure it was an example of thread galling, I feared that it might need to be a helicoil repair but once I'd purchased a repair kit with the right sized thread cleaning tap (M10x1) and cleaned all of the swarf out of the cylinder head thread with the tap, the new plug went in fine and tightened to the recommended torque ok (15nm if I recall).

Anyway, if they all crack off ok and don't go tight as you release them you should be fine. The only other thing to be careful of is that the connector bridge that plugs onto all four glow plugs starts life nice and flexible (it's rubberised plastic) but goes hard and brittle with age and disintegrates- be careful removing it. It can be replaced (as I did with mine) but ended up being a bit of a fiddle.

[attachimg=1]

[johnnyroper]

Recently done my e92 plugs and all 6 came out like that after much cursing over the space of an hour. Like you I was lucky that I was able to chase the thread with a cleaning tap. It seems the glow plugs are softer than head so are sort of sacrificial.
Had it been a PD I would have left the rest of first one came out like that,as it is on the e92 more than 1 knackered plug stops regenerations from happening so I was tied to sorting it.

[insanitybeard]

My understanding of the mechanism of galling is limited but metals such as stainless steel and alloy are prone to it apparently. In the case of the glow plugs on the Galaxy however, they definitely aren't made of a softer material than the cylinder head- the head being aluminium alloy and the glow plug as far as I can tell being some grade of stainless steel. This being the case you would think that the softer alloy head would have stripped the thread rather than the other way round, and although the thread in the head certainly wasn't completely undamaged, thankfully it cleaned up to be usable again, more than could be said for the plug!

I wanted to make the glow plugs were ok as I'd noticed the engine smoke a bit and struggle to start from cold during the colder winter period. As it was, I think my issue was more to do with the disintegrating connector bridge than the actual glow plugs themselves! It's a sinking feeling when you feel threads going tight after you've cracked them off, especially if it's on something which has poor access or will need stripping down to sort 

[johnnyroper]

The BMW ones seem far thinner and softer than the ones I changed on my galaxy.
I do t know a lot about galling apart from it is caused by the friction against threads causing heat build up.
When I refitted I used some anti seize (copper slip) to assist the plugs going down nicely ready for final 15nm torque.

I was determined not to have any snap though,there are companies that can sort snapped plugs but on mine if it was a head off job it means taking engine out.

OP follow the above advise about penetrating oil,warming engine and slowly going back and forth with 1/4 drive and you should be ok.

[insanitybeard]

Sound advice about using copper grease on install, I did just that when refitting the plugs- just a shame that they don't do it at the factory, which would help avoid these kind of problems in the first place! But then, how many jobs on cars would be made so much easier if the components were actually greased on the production line when assembled- steering and suspension components in particular!