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Glow plug indicator light, wherefore are thou?

14K views 10 replies 5 participants last post by  denzel  
#1 ·
The Great Handbook, which is of course always correct, has these wise words for me to remember when starting my 3008 1.5hdi;

"With a Diesel engine, turn the key to position 2, ignition on, to operate the engine pre-heating system. Wait until this warning lamp goes off in the instrument panel then operate the starter motor by turning the key to position 3 without pressing the accelerator pedal, until the engine starts. Once the engine is running, release the key."

All well and good, except no such warning light has yet shown its face on my dash display. I don't see a space in the array of lights where it could be. Has it been done away with on the new 1.5hdi, as a result of conforming to the Euro 6.2 standard?

I'm not concerned about the missing lamp - just curious! Maybe other 1.5 diseasel owners can comment.
 
#5 ·
I'm sure you're right Mr Lee. I thought the symbol would briefly illuminate just to show the circuit was working, rather than there being a need for the glow plugs to actually be in use. Let's hope we don't see too many -4° days to test it out, though! ?
 
#7 ·
Glow plugs do indeed come on briefly in cold weather but to be honest on ALL common rail diesels from around 2000 onwards they are not actually needed the light wont come on unless its really cold but the car will start fine regardless.

On more modern diesels with DPF systems the glowplugs are primarily used to heat up the exhaust gasses to help the regen process so they are required but have a different purpose they will still come on very briefly at starting but even if all 4 were not working the engine will still start.
 
#9 ·
I have the 1.6L, and the glow plug symbol comes on even when it is slightly above 0C.

For example this morning it was 4C and the glow plug light came on, the engine waited for a few senconds for the symbol to turn off and then started. So to me it would seem that they are used? Or at least the engine waits for the glow plug light to turn off before starting, they must be heating I would say...
It has been like this ever since I bought the car, in winter they are used each time when starting cold.

Could it also be that it depends on the market where the car is sold? For example UK vs mainland Europe where it is usually a bit colder in winter.
 
#10 ·
If you need proof of the lack of need for them unplug the relay and it will still start my sons 406 has NO RELAY as it was flattening the battery that was 5 years ago and we are in scotland car always starts :)

The engine does not wait for the light to go out though if you just jump in and turn the key the engine turns over regardless of light.
 
#11 ·
You are talking about you car, and I am talking about my car, two different things.

I am saying that when outside temperature is colder the engine does not start before the glow plug light turns off, and like I said this happens even when it is not below 0 C.
With warmer weather the light does not come on and engine starts immediately.
Will the engine start even with glow plugs disconnected? Yes, probably it will, since it is not -40C outside.

I am sure you are correct about your case, but with my car it does not seem to be the same like with yours.
In winter when it is for example -15C, the light stays on longer and engine waits before starting that much longer. Does that mean they are not used? I don't know, I did not pull one out to check if it gets hot or not. :)

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