Hi Folks , This is my first post so bear with me. I purchased my audi 12 months ago from a private dealership in Preston after months of searching. Found the love of my life and have loved driving my A4 eversince. About 3 months ago the engine started to make a gentle knocking noise on tick over once the car reached temperature. Did not appear to be any performance issues , had a full 60000 mile service and no faults registered. The noise started to get worse , took it to my usual garage and they discovered the fault. At the back of the engine there is a VVT chain and tensioner , this was worn and replaced , however the noise continued. one of the tech guys ( ex vag mechanic ) said that he suspected the Vanos unit. This was replaced with new, along with an oil change and a bill for £930 ( ouch ). The difference in performance was significant and the engine purrrrs like a kitten thank god. I've read a lot of posts on a number of forums but have yet to find anyone with the same issue. Very surprised that a low milage A4 with full VAG history should suffer a fault like this. Any feed back would be very much appreciated.