Hello, From about the time I first serviced my a3 1.8t quattro to now (8 months), it has made a rattling noise on startup and rattles on idle once it gets warm. I've recently had it diagnosed as 'cam chain tensioner' by a VAG specialist, although he did only give it the cursory look over whilst it was running. I'm currently looking at a £800 bill all told, for the VVT £400 OEM part and the labour, as I don't trust myself to fix something as serious as this. As a last resort I was linked to this thread on the ttforums: http://www.ttforum.co.uk/forum/view...s=0&postorder=asc&highlight=oil+pump&start=10 It states that startup and idle warm rattle could be attributed to a faulty non return valve found in the back of the oil filter bracket. For £15 + VAT, I think it's worth investigating before I put my car on the market and say goodbye for good. I've searched the forums for a guide on removing the oil filter bracket but not found anything of any use. Has anyone done this job before? Has anyone ever cured their rattling problem with this before? And if I am going to take off the oil filter bracket, do I have to drain my oil? Surely this is a very messy job. Thanks for reading.