Whislt sitting in the car my left side does not have one and my right side were there should be one also doesnt have one, obviously it should be there is there anything I would notice if it isnt in there and what effect does it have on the car?
They reduce the oil getting into the combustion system, without one you'll see more oil being passed through the combustion parts (plugs etc)
They also keep the inside of the engine in a vacuum (breath in from the L/H side and suck out from the R/H side) Not sure if this is affected with no seperator in place (i cannot see it would)
They are often removed as they clog up over time. Routine maintenance should be to clean them.