Regen cycle - how many failed glow-plugs stop it?

[X5Sport]

Having reset the fault codes after changing the battery I have a recurring failure of glow-plug #6. Having heard that the plugs support the DPF regen, anyone know how many need to fail before that also stops occurring?

Does it need all six, or will five do?

I need to get it booked in to have it replaced however given that they are all more than 8 years old I suspect doing just one may be a false economy so changing the lot (and probably the controller at the same time) may make more sense.

If losing just one cause the regen to stop then it will get done urgently. If not then I can get it done within a month or so.

[Alan Gunn]

On my e90 1 bad plug is enough to stop a regen.

[X5Sport]

I suspected that might be the case. Thanks for the reply. New DPF or new plugs and a new DPF if I ignore it....hmmmmm that’s a tough one...not.

[snrbrtsn]

I believe Alan is correct - So much for the song - it takes two baby.....

Surprising how active the regens are, I monitor coolant temps frequently and often see the temps ramp to 99/100 to signify regen.
On Carly parameter/dashboard, display coolant temp, dpf back pressure and particle mass so as a means of checking and confirming for yourself!
The coolant temp should rise to 99+ as the other two drop

[Leslie]

Think I have possibly at least one out as when its 0c its very lumpy for a few secs after a start , still regenning fine at the minute but need to get it sorted.

[marti]

One out on my X6 (e71) did stop the regen.......only found out when the DPF light popped up.......

[X5Sport]

It’s in to have the lot changed along with the preheater controller on Thursday. Some E-cars aren’t bothered, but I’m taking no chances. Just over £400 all in. I don’t have the time to diy at present and need the car on the road, even if I know I could do it. It isn’t unknown for the fine pitch threads to ‘pick-up’ or even snap and I can’t take that chance either. Ho hum.

Thanks to all though

[Glen]

Does the glowplug light still come on when a plug or 2 are knackered.
Cos on mine the glowplug light comes on but is lumpy for about 3 seconds after start up on really cold days

[Alan Gunn]

Does the glowplug light still come on when a plug or 2 are knackered.
Cos on mine the glowplug light comes on but is lumpy for about 3 seconds after start up on really cold days

Yes it will still come on.

[X5Sport]

Does the glowplug light still come on when a plug or 2 are knackered.
Cos on mine the glowplug light comes on but is lumpy for about 3 seconds after start up on really cold days

It certainly does on mine. The only reason I knew of the issue was because I ran a fault check after coding the new battery in. Not sure what drives that light but it could be the actual controller or perhaps the ECU/DDE which sends the command to it.

The Indy I use (Milton Keynes) said they won’t know if it’s a bad plug or controller until they’ve got at everything (and therefore need to take various bits off) so if they have to go that far then they might as well change the lot anyway. If one plug has gone the rest may not be far behind. A number of folks on here (and the Indy said the same) have found that if plugs fail and are replaced then there is a high likelihood that the controller will follow shortly after - and needs everything taking off again!

[X5Sport]

Well I can safely say that I am very glad that this work is being done at an Indy run by all BMW trained technicians (based on all the certificates around the waiting room) as this has turned into a bit of a challenge even for them!

A straightforward job of about 3-hours has turned into an 8-hour nightmare for them.

I was warned that the alloy N57 series engines are ‘known’ to give problems, but even they are surprised with this one. The first glowplug came out with no issues but on inspection of the threads they were damaged! The next two came out absolutely fine and the last three snapped! The standard procedure is hot engine, loads of release lubricant, go have a cup of tea and then remove plugs.

Cue choice language in the workshop, a lot more work and a helicoil kit being needed. It’s a good thing the plugs are offset or it would mean a head-off job to repair everything and keep any swarf out. I should get the car back tomorrow, and I’m very glad I decided not to diy.

No idea why this particular engine is bad. Could be a combination of car age and low mileage, or bad passivation, or just bad luck. Definitely one to think hard about unless you have the tools to deal with this at home.

[snrbrtsn]

Ouch!
That is a run of bad luck...
Is it worth having your scuttle checked, it’s known to allow water to leak and saturate the engine foam insulation, this may allow water ingress to plug sockets

Many who have carried out, initially identify the need to change
Soak glow plugs in penetrating fluid continuously for a week or so with frequent reapplication
On the chosen change day, run engine to temperature further soak plugs
Loosen all plugs working from back to front whilst engine is still hot

Though likely there’s some metallurgy issues going on to cause the threads to strip....

[X5Sport]

I would have expected the plugs to be passivated in order to avoid the different metals issue so common with aluminium. Dissimilar metals plus damp plus heat and bingo - a problem. Ali is terrible for this. It almost makes sense to put steel inserts in anyway given the likelihood of problems, but no doubt the bean counters disagree. At least I know that four should come out fine next time

Damp at the back makes sense as it was the rear three that snapped in their holes.

[Leslie]

Not making me want to change mine now lol

[LincsX5]

A scan on Carly is showing I have 4 glow plugs faulty but car is still doing regens, soot and ash levels low. Is it possible the controller is giving duff codes and the plugs are ok? I have repeatedly cleared the codes but they come back each time.