Hey guys, picked up a 99 Silverado 5.3 on Craigslist 150k, well problem is I have a annoying sqeuaking like a bird is chirping under my hood! I have replaced the idler pulley and the Belt tensioner and its still squeaking do you guys have any ideas what it could be? Could the A/C belt cause these little chirps I thought that would be a loud screeching sound but the A/C belt looks pretty worn and has some cracks. Any ideas thanks guys!

 

Any belt and pulley can cause that sound. Start by replacing any belt that looks damaged. If the sound continues check all the pulleys, any that feel unusually hard to turn, replace the component it is attached to.

 

If it's chirping, it's definitely a belt issue.