First, you should NOT power any motor from the Arduino 5v pin. It cannot provide enough current and voltage spikes from the motor can damage your Arduino.
Without seeing the datasheet for the motor it is impossible to answer your question - except by guessing.
In general 12v (compared to 5v) will cause a great deal more current to flow in the motor coils. That can cause the motor to overheat and get damagaed.
...R