The life and times of the humble glowplug...

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Wed 27 Jan 2010 11:28
The life and times of the humble glowplug... - Mr Moo
In the days of indirect injection diesel engines, glowplugs would have been needed for all cold starts and a fair few luke warm starts too. I seem to recall needing some new ones at around 90k miles on an old Peugeot 205 that I ran. In the main, I don't think they used to stay on to reduce emissions after a cold start though.

In modern DI/CR units, the glowplugs only really come in to play to aid starting in sub zero temperatues. However, I suspect that even if no yellow light appears on the dashboard, they may be used automatically after a cold start, to reduce pollution and aid smooth running for a few seconds.

Clearly, these devices have developed a lot in recent years and now heat up far quicker than they did a few years back.

Do you reckon that modern glow plugs in a modern engine that will probably start (eventually) in most conditions without their use, will last longer than in old IDI applications, where they were needed a lot, but perhaps didn't stay on after the engine had fired?

Will modern fuel injection systems and the quality of the fuel also contribute to a longer life for the modern glowplug...?
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Wed 27 Jan 2010 16:27
The life and times of the humble glowplug... - dieseldogg
Well I take it my 210,000 mile/12 year old glow plugs are still working as she started at -12 there recently
A bit reluctantly mind, but seeing as she is still on the origional untouched injectors and pump as well ???
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Wed 27 Jan 2010 16:49
The life and times of the humble glowplug... - DP
I had to change the (presumably original) glowplugs in our old Scenic 1.9dCi at around 50,000 miles. The funny thing is, if their failure hadn't put the MIL on, and triggered a scary "CHECK INJECTION" warning on the dash display, I wouldn't have known there was anything wrong with the thing. It started and ran perfectly normally.

I always understood that glowplugs in modern direct injection diesels actually have a harder time than in the old IDI engines, due to being energised for anything up to 3 minutes after the engine has started, for emission reduction purposes. On the old IDI engines, they'd come on for 5-10 seconds on a cold start and that was their work done until the next start.

Edited by DP on 27/01/2010 at 16:49

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Wed 27 Jan 2010 16:59
The life and times of the humble glowplug... - Dave_TD
Do you reckon that modern glow plugs in a modern engine that will probably start (eventually) in most conditions without their use, will last longer than in old IDI applications


The opposite, in my experience. My '01Y Octavia SDi needed new glowplugs after its first couple of sub-zero temperature morning starts - and even then it wasn't parked overnight long enough for the engine to get properly cold.

It was a minicab and was started probably 30-40 times every day, the vast majority of starts without seeming to "engage" the glowplugs. In fact I can only remember the glowplug light staying on for longer than the 1-second bulb test cycle on 4 or 5 occasions in well over 200k miles.

I've had other diesel cars too, on those the interior and instrument lights brightened perceptibly when the glowplugs were deactivated some 10-15 seconds after the engine had started - this never occurred with the Skoda.

EDIT:
>>being energised for anything up to 3 minutes after the engine has started

That could be why then!

Edited by Dave_TD {P} on 27/01/2010 at 17:00

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