DIAGNOSIS The motor is overheating due to insufficient airflow or a failing armature. The cooling fan is likely clogged with dust or damaged.
FIX Unplug tool. Use compressed air to blow out the air intake vents on the rear of the motor housing and the exhaust vents near the front. Check the fan on the armature shaft behind the rotor—you may need to remove the rear cover. Ensure fan blades are intact and spin freely.
IF THAT DIDN'T WORK The armature windings could be shorting, causing excessive amp draw and heat. This requires a motor replacement. Test by checking for sparks inside the housing near the brushes when running under load.
HEADS UP Let the tool cool down completely before continuing. Chronic overheating will cook the field coils and permanently kill the motor. Don't block the vents with your hand.