Dear MB forum,



I have a Mercedes-Benz Vito 122 CDI 2012 and there is a whistling sound that I can’t put my finger on where it comes from.



Please see video


Whistling sound occurs sporadically when driving between 50-100km/h most of the times at 70km/h. Over 2000rpm sound goes away.



Sound gradually increases, if you keep the car under same conditions (speed, throttle) sound continuous to whistle. As soon as you give more throttle and bring it over 2000rpm sound goes away. Same if you release throttle and let car slow down sound goes away. Changing gear manually up and down the sound continues as long as speed is the same.



I don’t se a relation between steering angle and sound, sound continuous even when turning steering wheel.



As seen in video sound continues when driving and putting gearbox in neutral.



It sounds like something is oscillating but I can’t put my finger on what it is.



Does anyone have an idea what it could be? Any advice would be greatly appreciated.



Thanks in advance.