Following this thread ... http://www.astraownersclub.com/vb/sh...d.php?t=145193
Just cleaned my ERG valve, took about an hour, I used wd40 as I didnt have any carb cleaner. its a 14,500 mile CDTI 150, you wouldn't have thought it would be that bad. Loads of carbon in there - quick test drive revealed almost no smoke now, before there was smoke at low revs / low speed. More power from cold now, pick up much better.
If you run a diesel and you haven't done this have a look at it. Its an easy job and took me about an hour. Follow the thread step by step.
Thanks to Sticky for posting the How too !