My 2011 135i M-sport Vert which Ive owned since new is about to come off warranty. I took the car in for service and asked them to have a listen to my engine (N55) at cold start, because sometimes there is a rattle. I figured it was something actually just loose and slapping around, like a wire loom or something, but wanted them to check in case it was the VANOS bolts that are currently recalled without available parts... Anyway, I got this back:
Does anyone else know of valvetronic issues where the actuator and/or eccentric shaft sticks or binds? Seems to me like it was probably a very expensive job, if not under warranty... But the thing was: the car ran perfect and beautifully, it had tons of power and great MPGs, there was never a CEL, it never acted funny starting up or operating, I have a boost gauge on it and it always gave strong boost per spec.
This car doesn't actually pull a hard vacuum at idle, it has that throttle less design which just overlaps valve timing. That's my issue. Car ran great, still does, so I guess only a cold start analysis (listening closely t many cold starts after sitting overnight... Of course now it is the summer so it probably wouldnt have happened in the heat anyway) in the future will say. I can't say that I've even listened for the noise recently (was in the winter), as it was only notable if standing right in front over top of the engine. Again, this was really just a CYA for those VANOS bolts, since though they are recalled, there aren't parts and my factory warranty is about to expire.
Frankly I was surprised that they did this, on a car with no faults or issues. I guess Im glad and grateful that they did. I just want to learn more... Was this a freak thing since I was sort of a beta tester of the N55 (picked up my '11 135i in July of 2010), or is this more well known than I thought?
Thanks!