I'm relatively new and its possible after 18 months of lurking this is my first post - embarrassing! And it needs to be said I am beyond grateful for everything I've learned from the time spent here. Amazing.
I started following this thread when I too experienced the difficult start phenomenon in November (it actually happened during last winter too). The car had sat for several days and it was cold, colder than most late Novembers but not ridiculous like the midwest. The symptoms are identical, attempts to start over 10 to 15 minutes like this: crank with no start a handful of times, crank and catch but quickly quits then crank again with nothing, crank with a start but the idle is incredibly rough akin to running a gas engine with water in the line (ask me how I know). It ran so rough it was scary.
Contacted the dealer - who now claims to be the largest in the USA located outside of Boston - and brought the car to them. It sat with them overnight and they "could not reproduce the problem." Had them do an oil change and went home.
Then comes Christmas week and the car sat for a few days and again was very hard to start. This time based on my research here I did not persist in trying and called the dealer immediately. VOA got involved and sent a flatbed and off it went to the dealer for 3 or 4 very cold days with a 20" blizzard on top. Perfect, right? They called to say they had "located the issue" and it was a "defective glow plug" which they claim to have swapped out. According to both service reports (the most recent and the one in November) the tech confirms "no water in the fuel and fuel filter", etc.
Come to this week, the car sat for a day or two and again starts but runs very rough. So I might credit the glow plug replacement with helping a little there is a lot of improvement needed before I can say it starts smoothly.
Not quite at the end of my string on this I did contact VOA yesterday to explain the continued issue and lack of progress. They listened and said they would escalate and bring to the attention of the regional whomever and it would go from there.
I will be update this thread as this drama unfolds.
Thanks again for everything, you've helped this owner a lot.
By the way, this is my second VW diesel, my first was a 1978 Diesel Rabbit I bough new while in graduate school.