Hello everybody, this is the my first post so please go easy on me if I don't sound too knowledgeable! I'll try to keep this concise. I have had an Audi A3 8P body, 3-door, 2.0TDI for just over a year. Yesterday I was driving my car towards a set of traffic lights in second gear at low revs. When the lights changed to amber I pressed on the accelerator to pass, but then there was a snapping sound which came from underneath the car, as though I had ran over something. The best way to describe this would be the sound that's made as if snapping a leather belt that goes around your waist to keep your trousers on! The car then juddered as if the car was struggling to go forward in gear and then a lot of white smoke started to pour from behind out of the exhaust pipe. After I pulled over, I switched the engine off to let it settle until the smoke stopped. I checked underneath the car which showed nothing leaking or snapped as far as I could tell. I then tried to switch the engine back on but it wouldn't turn over at all. It just makes a single knock sound and will not turn. A friend had said to check the engine oil level which I hadn't done in a long time. I found that the level was too low beyond the measurable level of the dipstick. So I added 2 litres and it registered on the dipstick. I then tried to turn the engine over again and still the same sound. The car is currently with a mechanic who says it will be approximately £800 for a replacement engine and £300 for labour. As I am not at all mechanically minded, I would appreciate any thoughts and information people can give me on this issue. I am also trying to look around for replacement engines myself but I am not sure of all of the different engines that my car can take. Can somebody respond with a list and engine codes if possible? Thanks for your time and I appreciate any help you can give me.