Can anyone confirm that my 2004 545i (160k mileage) may need a crankcase ventilation valve replacement? No hydrocarbons were detected from the coolant reservoir and the engine fault light is on and from one of the two internal vacuum hoses (code: P0491-secondary air injection system) which, I believe this valve attaches to. My car produces white, sometimes with a little bit of blue in it, smoke after idling for as little as 15 seconds, but it is not consistent. Some days no smoke is produced other days at almost every third stop light it occurs. Are these signs of a bad crankcase ventilation valve? Is the replacement of the part very similar to the video seen on YouTube for an older model being that my car is newer? Your help is appreciated? Mark
