hi all, i have just brought an a4 which has been standing for a while 11 months ish, just had new mot on it, and drives amazing, its around 150k but drives like a much younger car, main question is when i switch off engine after a run there is a hissing noise from engine bay seems to be from expansion tank area. the length of time can vary not seemingly related to the length of drive. also have had a couple of times when temp sensor reads 60 on motorway then returns to 90 but not ever over in traffic??? oil temp never seems to rise above 60 either??? am i missing something?? please help am totally now an audi man but just learning the ropes regards luke.