A coolant flow reduction monitoring system for a rotary electric machine having stator coils within a plurality of slots of a stator thereof is provided. The stator coils are cooled by a coolant flowing in a plurality of passages provided in the stator coils. The system includes an outlet temperature sensor for measuring a coolant outlet temperature of the coolant in an outlet of at least one of the plurality of passages, a slot temperature sensor for measuring a temperature in at least one slot at a location along a length of each slot and outside of the stator coils, and an inlet temperature sensor for measuring a coolant inlet temperature of the coolant. A coolant flow reduction monitor generates an alarm indicating a coolant flow reduction based on the at least one coolant outlet temperature, the at least one slot temperature and the coolant inlet temperature.