This beautiful flagship sedan would whistle while the engine was running, with poor engine performance.
The oil separator had failed – simple enough. Unfortunately Audi has packed everything so tightly into the engine package that a fair number of stuff has to come out in order to access the separator.
It’s impressive how much they can stuff into such a relatively small volume of space. Not sure how well the oil cooler and oil separator can hold up directly under the turbos, though.