any idea what is causing this? its not my car - posting on behalf of another member. he picked up a 2013 certified RDX... should be under warranty but he did record this ... seems like a droning humming sound or a vacuum cleaner. its louder than it is than in the video .

 

Out of curiosity, why is the other member not posting the question under their own account?

 

doesnt have a youtube account to host the video.

 

These people do not try to answer your question [in the first place] and even resort to questioning why you posted the question instead of the RDX owner ...

... Most likely this 'sound' is related to the VCM (ie shitty VCM). 2013 engines use a different VCM system (1st iteration) that the one implemented in more recent models. From what I can remember these 2013 engines can work in 3 modes: 6, 4 and 3 cylinders. In some of the modes the engine does not work properly balanced and the [adaptive] engine mounts are not adaptive enough to dampen the vibration. It manifests as a subtle, bothering, stupid vibration/droning sound that is mostly felt at the steering wheel, shift stick and pedals. For some people this is not important, for me; wow it would make feel me miserable to be driving a 40k vehicle with this situation.

This situation, together with a highway vibration that the Acura technicians could not fix after 5 or 6 tries, made me reconsider and decided to ditch the RDX, losing considerable $ in the process. I still lurk this forum from time to time and [from what I hear], apparently some of these problems have been ironed out, but I think it will still be a LONG TIME until I trust Acura again, if ever. Appearances are very subjective but, in my opinion, recent Acura models are bland and up to some point flawed, and many people have lost the trust in the brand. For me, not more VCM or something like that (although other makers make this system totally seamless as it happened with my late 2009 chevy avalanche -> I could never determine when the system was on because it was truly seamless)

Tell your friend that, most likely, there is no much to do about the humming sound [I learned the hard way]