You should test it with Seagate's own diagnostic software (SeaTools for Windows) instead of relying solely on the SMART data. The SMART warning flags will vary according to the utility software you use to view it because the threshold settings will be different depending on the utility.
Get SeaTools for Windows here and install it: http://www.seagate.com/gb/en/support/downloads/item/seatools-win-master/