What causes the abnormal noise from the engine timing belt?

[Cory]

When encountering abnormal noise from the engine timing belt, first check the assembly. The noise may be caused by friction between the timing belt and the timing cover. You can loosen the screws on the timing cover by half a turn to observe if the noise disappears. Next, inspect the condition of the generator belt, as the noise might originate from the accessory belt. If the timing belt tension is adjusted too tightly, remove the generator and air conditioning power steering belts to rule out whether the issue lies with these belts. A faulty timing belt tensioner usually requires replacement along with the timing belt. The noise could also be due to issues with individual engine bearings, so carefully identify the exact source of the sound. If the specific cause cannot be determined, it is recommended to visit a professional repair shop for inspection to pinpoint the issue.