I have a chirping sound and it seems my serpentine belt is crack free and tight enough but a chirping sound is coming from the alternator and pulley areas around the front of motor.this sound seems to occur after car has been running for a while.i do have a good mechanic but i want to know if it could be the timing chain which i pray it isn't.i believe loudest part of chirp is near the alternator.it has been replaced 5 years ago.i will check for a wobbling pulley otherwise i am clueless.