The K-7 sensor clean is somewhat audible, especially without a lens attached, has a very hight pitched sound to it. I guess it varies from camera to camera. The K-5 sensor clean is so quiet you cant hear it.
Im one of those who take the lens off and try to put my ear inside the camera. Maybe i heard something in the K-5
Can not say for sure though!
The SR: In the K-5 the SR turns on almost instantly after half-press, a big step up from the lag in the K-7.
You may have a defect camera, we cant rule that out, so....
Hand hold the camera with your lens at 50mm or so. Select a medium slow shutterspeed like 1/30 and set aperture and ISO to get a nice exposure.
Now, half press the shutter button and pan the camera in circles in front of you (imaging that the camera is inside a car on a bumpy road). Take the picture, then turn of SR and do the same. Experiment a litle....
OR, this is easier! Turn the camera into Live View, move the camera, can you hear the SR working?