hi first time driving an Audi 90 2,3 with ng engine had recently changed my engine because this on 5 cylinder very strong flapper noise had now driven the “new” engine inside about three weeks and now the engine starts to clap just as the first engine of the oil pressure sinks in empty run according to the indicator in the cockpit to zero bar (know that I may not go after the display but it is still a small help) when giving gas he goes to about 5 or 6 bar the greek is but also not always when I drive longer distances e.g. land road the noise does not occur rather only in urban traffic the oil-warning lamp starts but not the light does it work but with old motor lights it has also led a motor inside cleaning through has unfortunately also not helped the oil-pressure decreases with operating warm engine but with fresh oil when giving gas it rises again it can possibly lie on the oil pump that hangs there a pressure valve or something like that in style if yes the expansion of the pump is done quickly or is that something long-viral? in another forum one has said what of the underpressure pump that the cause of in noises what I do not think very promising the search I have used but did not find any entry with such a problem thank you already in advance