About a year ago, i noticed excessive smoke from the exhaust, only visible though in cold weather. Car went back to Audi dealer twice, but they were unable to idenitfy problem. When issue got worse they told me it was a sensor in the exhaust, which got changed. (cost >£500). Following winter, same issue, but also noticed slight growling noise from enginer bay following 70K service. Car went back to Audi, engine stripped down and cleaned due to excessive build up of carbon !. (another £500). When car returned problem still exists.
Back to Audi again; following 3 days of investigation by Audi Dealer, i was told that the smoking issue was caused by failing injectors and that the growling noise was due to a problem with the turbo and that all would need to be replaced at a cost of £5800. Managed to negotaite this down to £2500 with good will gesture from Audi. Work has been undetraken, but still getting the low level growling noise. Audi dealer admit they can hear the noise, but cant identify the root cause. Have told me to run it for another 1K miles and see what happens !.
Just wondering if any of this sounds familar to anyone with an A4 3.00TDI and if so, what was the root cause ?