I think I have seen your post on the Holden Cruze Facebook page, I live in Sydney. The US diesel is a different engine and their manual would be useless. Are you in a motoring organization similar to the NRMA, as they may be able to help you find the cause. If you have the series one engine 2009 - 2011, it will be different to the series II 2011+. I have an owners manual for the series II but I don't think that will help much. This may sound silly, but see if your dipstick is bent as I know of 2 different cars that developed a knock only to find a bent dipstick was being hit by the crankshaft.