This paper intended to explore the performance losses in outer rotor BLDC motor due to Permanent Magnets. Magnetic Aging and Surface level damage are biggest thread to Permanent magnet motors. In BLDC motor based electric vehicles, especially in In-wheel propulsion, Permanent magnets plays vital role in torque development. But naturally those magnets are more vulnerable to Nature, specifically to moisture and Corrosion. In this paper, detailed investigation BLDC motor with corroded Permanent magnets has been carried out. Each power loss components have been modelled to estimate the losses occurred in this motor. Due to corrosion, the effective magnet length towards the magnetizing direction has been reduced. This reduction directly impacts the flux concentration because of change in physical dimension of the air gap. The entire operation of the motor has affected. This change is air gap length initiates losses in both stator and rotor of the motor and ultimately reduces the performance of the motor. A real time corroded Permanent magnet motor has been investigated to analysis the possible level of performance reduction in BLDC outer rotor motor. The detailed Thermal studies of the motor have been performed with corroded magnets This paper extends to various ranges of Power rated motors affected by surface level damage in Permanent Magnet motors to understand the behaviour of the Permanent magnets in Electric Vehicle Propulsion.