2005 Avant 1.9 Tdi Oil and noise
 

I have a 2005 Avant 1.9 Tdi, which I bought about 3 months ago. Has performed amazingly - average fuel consumption of less than 6l/100km and drives really smoothly. It has however been using more oil than I am used to(this is my first diesel Audi, previously drove BMW diesels). I was told that up to 1000ml/ 1000Km is still within spec. I am using more than 500ml/1000km at the moment. It does smoke more than I would of thought acceptable. Performance is fine. I have checked the play in the turbo shaft and seems to be ok. It has recently started making a very strange noise when lifting my foot of the accelerator - during changing gears or slowing down - sounds like an exhaust brake on a big diesel truck. Performance is still perfect. Any ideas or advice would be greatly appreciated.