Hi,
When the car is at idle and the A/C is turned on I can hear a clunk sound every 12 seconds.
I have looked at the engine and it seems related to the A/C compressor. When the belt is moving the A/C which is under the alternator does not spin. Every 12 seconds you can see the pulley start up and spin. This is when it makes a clunk.
However, it only spins for a second then stops. 12 seconds later spins up again with a clunk.
Is this normal. If I turn the A/C off it does not happen.
