Last week, whilst driving on the freeway, my 2009 330D (N57 engine) suddenly lost power. I was able to guide the car to the emergency lane.
There were no warnings shown on the I drive display.

The car then refused to start (engine turned but did not start), so I had to get the car transported home on a truck.

On inspecting the engine the following morning I found that the car would only start with the breather pipe disconnected, but it threw out a fair amount of oil from the cylinder head cover outlet end.

I have since replaced the cylinder head cover (after being advised ) but the problem remains.

Prior to this incident, the car was running fine with no indication of any fault, and the oil service was performed about two weeks before.

The indie mechanic assisting is now out of ideas as to the cause.

Please help. Thanks.