62°C? That's just insane. IIRC even the WD Black I got in bay 4 hardly got over 45° during the day.
However, instead of ripping apart the external Seagate, I'd rather buy an internal 3TB WD Green. Not only because I prefer WD over Seagate, but also because you get 3 years of warranty instead of 0 in case of the DIY external-internal approach.