sound coming from engine bay

[AY8686]

Was curising along highway, heard some screeching sound, sounded like pulley sounds any idea what isit ? but when i turn off the air-con, the sound disappear

[CES KLASS]

Was curising along highway, heard some screeching sound, sounded like pulley sounds any idea what isit ? but when i turn off the air-con, the sound disappear

Bro, I may have the same issue, let's share cos the time I drove to c & c workshop, the sound doesn't appear, sianz! Anyway, did you stop the car to examine? Is the sound coming from around the left headlamp area sounding like ringing tone very prominent even without opening the bonnet? Will disappear after switching off aircon?

[AY8686]

Bro, I may have the same issue, let's share cos the time I drove to c & c workshop, the sound doesn't appear, sianz! Anyway, did you stop the car to examine? Is the sound coming from around the left headlamp area sounding like ringing tone very prominent even without opening the bonnet? Will disappear after switching off aircon?

bro im driving w212 e200 facelifted model. you driving the same? the sound is coming from the engine bay bay but duno which part but when idle theres no sound only when curising.. 

[CES KLASS]

Oops sorry bro, I am driving w204

[AAAAA]

Sound like a faulty compressor....noise wil get louder. Just like your aircon at home, when its new, it's super quiet, as they age It becom louder.which to tell you, u need a change or live with it.

[seigedan]

I have the same problem too, the sound goes off when Air-con is off. Could it be compressor bearing?

[jon]

When the timing belt wear out, it will have screeching sound too.

Perhaps check when is the last time you change all the belts...

[blackmercs]

Timing belt or chain?