The 26-year-old forward has been in wonderful form since arriving from Rayo Vallecano in the summer, scoring 10 times.
And despite only joining this season, Rangel feels they need to consider signing him to a new deal.
"That's something the club has to consider and he is a player we can't afford to lose," Rangel is quoted by the Daily Mirror.
"Hopefully he will stay here for a long time and we can have good success.
"Not many players can score 10 goals in the Premier League. He has done a fantastic job. He gives us an aerial threat that we probably lacked a bit before.
"He is feeling comfortable, enjoying his life in Swansea and everyone is happy with him."