echo512

Hi,

Recently, when stopped, foot on brake, and A/C on, the engine drone (humming) is louder. It goes away when brake is removed, and is not present when braking but moving. Just happens when the car stops. It also stops completely when I turn off the A/C.

Ideas on this? belt/pulley issues?

Plutoe

At home, lift the hood take a look about and listen while the driver duplicates (humming) conditions.

apl175

Drone or groaning that is dependent on A/C compressor is likely caused by the compressor pulley. This is a documented issue with some W211 vehicles.

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