Q: Squealing noise coming from engine

Hi there, the Corolla has a timing chain that won’t make a squealing sound because there are splines on the inside of the belt/chain to prevent slipping. There are tensioners and pulleys that can wear out over time causing unwanted noise from under the hood which could be happening. Typically, however, the serpentine belts are the cause of a squealing sound from underneath the hood. These belts power components like the water pump, alternator, and A/C compressor (if the car is equipped with A/C). Over time, they can lose their grip which will cause them to slip on the pulleys creating a squealing sound. If the belts haven’t been changed recently it’s most likely time for a replacement. Have a certified technician inspect the belts for you to find the cause of the sound.