Considering that you have been using it for 5 years, it's better if you can change one.
And the Service Tag is not necessary for the fan change.
If you call DELL Service Certer, then the Service Tag will be needed.
You can just check the pn on your fan or just fill in " Inspiron 15z 5523 fan ", then search it on Aliexpress, ebay, or Amazon.
You can get a plenty of choice.
Hope you can solve your problem.