[golfergavnz]

hi guys and girls I have a 2008 i30 diesel
is it normal for the glow plug to take what seems like at least 10 sec to go out before I can start the car
I on occasion drive the work holden rodeo diesel and I can just turn key and start straight
could there be a glow plug problem or battery or both
your help would be appreciated

[Phil №❶]

No, that's normal behaviour. 

[The Gonz]

I guess it's purely temperature related (duh!).
Mine takes about the time the radio kicks in, so probably a second or two. It's so consistent I now sometimes turn the key when I hear the radio even without watching the light.

[Asterix]

I've never had to wait 10 sec before the glow light went out, not even when there was -20°C out there....

Not sure what the problem is, but it's not normal.

[Ted11]

seems about normal ,you should hear relay under bonnet click out before the light goes out and is related to temp.
is it the same when engine is hot ?

[Asterix]

The glow plug relay use the engine coolant temperature to determine the necessary glowtime.

If the temp sensor is faulty then the glow time will be wrong, e.g if the temp reads as -40 °C   This will of course not be logged as an error in the ecu, so to find out you need to have a scan gauge to read the temp or the dealers computer can tell you.

If this is the case, then the overall consumption will most likely be affected as well.

[Asterix]

seems about normal ,you should hear relay under bonnet click out before the light goes out and is related to temp.
is it the same when engine is hot ?

The glow plugs actually keeps glowing after the light goes out, up to 30 sec more depending on engine temperature.

The light only goes out to let you know that the temperature in the combustion chamber now is high enough to start the engine.

[i30niko]

I live in Australia and the lowest temperature we had over winter was 0 degrees Celsius and the glow plug only took 3-4 seconds max.
I think 10 seconds waiting time is excessive for any temperatures above zero degrees. Call a hyundai dealer and ask them.

[golfergavnz]

Hi thanks for that
When the car has been driven and at operating temp it  starts
Instantly even  after  about 2 hours

[StuMac]

From my days doing auto engineering at college (although worth noting this was ten years ago) glow plugs usually reach very high temperatures (usually around 600-800 degrees C). It is not unusual for glow plugs to take 10 seconds to reach operating temperature. So its not a major problem.

Things to look out for -
i) Problems starting the car irrespective of weather.
ii) A lumpy idle when cold.
iii) Black smoke when cold (not white, all cars get condensation in their exhausts, white smoke indicates the water is evaporating, black is fuel not burning correctly)

These can all be indications that the glowplugs are not reaching the correct temperature.

Unless you get any of these symptoms, there really shouldn't be too much to worry about.

[Phil №❶]

Sorry Stu, but there is a difference between white smoke and steam. Unburnt fuel that has NEVER been ignited is in fact whitish. The black you refer to, is improperly burned fuel where the air fuel ratio is incorrect for complete combustion. I have observed the white smoke characteristics and it does not evaporate into the air, but dissipates as you would expect smoke to do.

[StuMac]

I agree with what you say, there is indeed a difference in thick persistent white or grey smoke and steam. However grey smoke often points to a different problem such as a PCV, auto transmission issues, turbo problems, Coolant being burnt, but this smoke is typically more grey than white. But that's a whole other can of worms.

But white smoke from a cold start is 99.99% of the time due to water. My comments were only in the context of a car with potential glow plug / cold start issues.

[cruiserfied]

As Phil has said white "SMOKE" on cold start is un-ignited fuel and is almost always a glow plug issue. Not to be confused with steam.

[crazykev]

Hey mate yeah the behauviour of that light is pretty useless, my glow plugs were completely stuffed and not working at all and the light was still going out so figure that out. Its like the other bloke says it must work out the time based on coolant temp but it dosent actually know if the plugs have glowed. Mine was at 115k when I got it and none of the 4 would take any current when glowed so hyundai replaced all on warranty.

The car glows the plugs a little bit when its running cold to improve cold running so it probably leads to early glow plug failure.

[Morten martinsen]

You probably got one or two malfunction glow plug, its a common problem, at least her im Norway.
You should take it to a workshop and get it checked out.
It is not an easy job, they have an ugly habbit of breaking when you shall remove them. So let the mehcanic do it. And as some say here, the glow plugs are operatin even after the light turn off. And that are called active glowing.