Evaporator Fan Shaft Washer

My fridge was missing this part after a warranty repair, and I found out when replacing the evaporator fan motor. It is a thin brown washer tightly fitting over the shaft that I expect is there to limit vapor intrusion to the motor and limit friction between the fan and motor, so the motor will last. It should be a standard part that comes with the motor, not needing to fork out another $15 for. I cannot comment on the longevity - I replaced the second motor on my fridge, but it was still working. My fridge had a leaking freezer door (bottom) so as a result the first motor failure was due to Electrolux.