Glow plug life

Barrelsaver

New member
When starting my NCV3, I used to always wait for "elect squiggle" light to go out in the instrument panel display before I hit the starter. After replacing two glow plugs about 30,000 miles apart, I now just turn the key all the way to the starter without the "glow plug pause" and my engine still starts instantly. That "glow plug pause" must be for very cold start conditions! Anyone else have experience on this?
 

smiller

2008 View J (2007 NCV3 3500)
If you look carefully, after turning the key on (but not starting) the glow plug light will extinguish after about one or two seconds (under warm ambient conditions.) It happens so fast you'll miss it unless you are looking for it.

Pausing for the glow plug light isn't really necessary when it's warm out but I do it anyway, not sure why.
 

sailquik

Well-known member
Barrelsaver,
In warmer climates, you may not really "need" the 1,000 deg. C temperature generated in each cylinder by your Beru glow plugs, but until each cylinder actually fires your injectors are spraying diesel fuel into those cold cylinders with nothing but the heat of compression to cause the mixture to fire.
This can cause fuel to condense in the cold cylinders and wash down past the compression rings on each cylinder.
This "wash down" breaks the lubricant film on the cylinder wall and can cause abnormal wear on the cylinder and the compression rings on each piston.
So, the momentary 1,000 deg. C glow plug cycle prevents this as when the fuel is injected (at very high pressure in a spray pattern that is more easily ignited) there is a heat source to ensure that it ignites the first time the piston comes up and compresses the fuel/air mixture.
We all probably miss that ~2 second delay once in a while when we are in a hurry, but to do it routinely cannot be good for your engines longevity.
You also need fully functional glow plugs to increase your engine's temperature and ignite the extra rich fuel/air mixture that
occurs when your Diesel Particulate Filter (DPF) does it automatic regenerations to burn off accumulated soot in the filter
matrix and turn it to dry ash.
So, you can skip the glow plug cycle when your engine is started up after a cold soak, but you do so at your own peril.
Hope this helps,
Roger
Here's a link to some more information on the temperature/cycle time/overall function of the glow plugs in
you OM-642 3.0 liter V6 engine.
http://www.beru.com/download/produkte/TI04_en.pdf
 
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Barrelsaver

New member
Thanks Sailquik, for your very informative reply. I had now idea that there was a lubrication issue involved in the cold start process. I'll keep them burning now!
TK
 

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