My v6 2.7 TDI is getting on for 6 years/60k miles old and is still on the original glow plugs. I've notice a bit of roughness and a little more smoke (unburnt diesel) at cold start up recently even when waiting for the orange glow light to go out. I think it's only in one or two cylinders and soon clears as the car gets going.
In the past, this was a sure indication of glow plugs requiring replacement. How do I prove this at home please as I don't want to buy a set just in case? Assuming replacement is required, any recommendation for suppliers please?
Shouldn't be glow plugs at 60k. Try chucking a tub of injector cleaner through it, change the fuel filter, and at risk of upsetting certain other forum members (cue full-on STW cock-fight) use forecourt fuel instead of supermarket... 😛
Oh and then go and cane the tits off it to clear the DPF out.
Fuel filter changed ~5k ago, gets regular Italian tune and errr, no DPF 🙂
measure the current draw with one of these[img] 
[/img compare with operating specs, should be about 60 amps, ie 15 amps each. or get the breakdown out, they will do it
sounds like you didn't win 😉cue full-on STW cock-fight
Oh and then go and cane the tits off it to clear the DPF out
Transits at work have similar issues, the maintenance chap and I regularly sit redlining them in too low a gear for a couple of mikes to clear em out, works wonders.
You can normally tell by the glowplug light within the car. It should go off within within a few seconds if not they are getting warn. Removing one and connecting it to the battery will show you if they are working or not. At less than £50 a set I'd replace them at that age anyway.
Different car but one mine at similar age 3 out 4 weren't working when I removed them. The car was lovely and smooth again after replacing them.
Locate glowplugs pull off wire leading to them. To test them you can either have a wire connected to the battery and "stroke" top of glowplug, should spark as the glowplug is earthed properly, if it doesn't then broken glowplug do it to all of them.
With the offending glowplug remove from head then you can test is again be giving it a live feed and earth it should glow red hot, if not broken.
Bit complex explaining but dead easy in reality. If all glowplugs are sparking then they're working properly then you'll be looking at the glowplug relay.
Ok ta. Are they a reasonable suspicion at 60k/6 years?
Bit complex explaining but dead easy in reality
Provided you can get them out easily...