What sound indicates a starter motor is clashing with a spinning wheel?

The sound that indicates a starter motor is clashing with a spinning wheel is a grinding noise. This sound occurs when the teeth of the starter motor's pinion gear fail to engage correctly with the teeth on the flywheel. Instead of meshing smoothly, the pinion gear can slip or graze against the flywheel's teeth, resulting in metal-on-metal contact. This contact creates a grinding noise, signaling that there is an issue with the starter motor's engagement with the engine's flywheel.

Other sounds mentioned, like a popping sound, might indicate different issues entirely, such as fuel igniting in an undesirable manner, while a whirring sound typically suggests that the starter is running but isn't engaging successfully. A clicking noise often points to an electrical issue, like insufficient power reaching the starter, rather than a mechanical conflict between the starter and the flywheel. Thus, the grinding noise is specifically associated with that clash scenario.