1.6HDi glow plugs how important?

[xsara92]

Do they play any important role in the HDi design beyond essential for (icy weather) cold starts?

Mine has it's glow plug relays out, possibly just one, garage man said not to worry, however I've noted for a while that my engine sounds unhappy on cold starts..

[GiveMeABreak]

Well yes, they do. They are used for pre and post-heating by the engine ECU.

HDis are well-adapted to starting without glow plugs unlike the older non common-rail diesels in temperate conditions, but are used in cold conditions to aid starting as also aid particle filter regeneration and emissions reduction.

The pre-heater plugs enable a rapid rise in temperature in the combustion chambers during the starting and cold-running phases.
The pre-heater plugs are also used for depollution, contributing to the reduction of nitrous oxides and soots.

There are 4 modes of use for the pre-heater plugs:

• Pre-heating
• Pre-heating under starter
• Postheating
• Postheating for regeneration

[xsara92]

Useful info, thank you
Are there any figures for how long the engine coolant temperature should require to rise from minimum?
Sometimes, my engine is showing min. temperature for 10 mins.

[GiveMeABreak]

I wouldn't say that is unusual. Mine can take that long before it gets to normal operating temperature. It all depends on external temperature of course and how cold the engine is before it is started.