Poor solder connection, broken wire, bad bearing in the motor, binding in the drivetrain, or debris inhaled by the motor can all cause this. Swap motors with someone and see if it heats up in his car.
*** The Gate - Celebrating 7 years at the same location ***
The difference between genius and stupidity is that genius has its limits. - Albert Einstein
Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car