What are the reasons for a starter motor failure?

[MalachiRose]

The starter motor may fail due to the following reasons: 1. Abnormal noise during startup: If there is abnormal noise at the moment of starting, but the noise disappears when the engine idles after starting, the fault is likely caused by a problem with the carbon brushes inside the starter motor. 2. Abnormal noise during engine idle after starting: If there is abnormal noise when the engine idles after starting, the fault is likely caused by excessive clearance between the hydraulic lifters and valves inside the engine cylinder head. As the vehicle accumulates more mileage and years of use, both the engine valves and hydraulic lifters will experience some wear. This wear leads to excessive clearance, resulting in a "ticking" noise. To resolve this issue, the cylinder head needs to be disassembled to replace these two components.