If buck is with you and he wont leave than you didnt get the magma stone, go and find it. once you do (actually buck takes it), go to the survival area in the house next to the Pokemon center and talk to buck, then go back to stark mountain, enter the room where you got the magma stone, and catch the heatran that will be waiting in there for
Buck's house is in the survival place when you are going to Stark mountain next to the Poke center
he is in the top left house in the survival area ,talk to him then you can go and catch heatran at lv.70 ( first you have to help him get the magma stone in stark mountain!) the best ball to use is a dusk ball (get its health down first!)
he goes to his house that is in the survival area. I think that is the one that i at the left of the Pokemon center, after that go again to stark mountain and go to the place where Buck (that is he´s name) took the stone, there you will find a legendary Pokemon. After all this he will be in the Battle Tower to help you on Tag battles. Note: The second time you go to stark mountain you will be alone, so take some potions and revives. Good luck
First you need to go to survival area and go to the door that was locked and enter and then go back to stark mountain and go back to where team galactic and heatran willbe there. Hope I Helped
You go back to the Survival Area and go to his grandfather's house (the house on the left of the Pokémon Centre) and speak to him, then to Buck. Buck will then leave the house. When you go back to Stark Mountain, and into the room the Magma Stone was in, there will be Heatran in it's place, ready to be caught. Best of luck.
In smaller words go to survival area, then talk to Buck and he says he will put the stone away, so then go back to the mountain and you battle Hetran!!!.
after buck gets the magma stone go to the survival area and the house on the left of the p.c. go inside you will see buck talk to him he will say something about putting the magma stone back then he will run off then go to where he got the magma stone before and you will see heatran
After you beat Cynthia, Go to the island with the Survival Area, Travel to Stark Mountain, Go in and get to the top, When your follower leaves(who you pick up in the mountain, he has red hair) leave and go check all the houses in the Survival Area, Red Hair(Buck) gives you item, Go back to the mountain to the room in which your Red Hair (Buck) follower left and Heatran should be there, Save and go to catch him
start from your villa and move left. cross the bridge and pass the two trainers and keep going up then left.get through the sanstorm and go left the sandstorm will stop and there will be a huge patch of grass there.go up and the area is stark mountain
what you do is you go to the survival area and go to the house on the left side of the Pokemon center. talk to the old man (buck's grandfather) then buck. buck will return the treasure back to where it was. go back to stark mountain and pick up the treasure, but you should save first because if you make heatran faint then your probably thinking to turn off the power then turn it back on. then get ready to fight and catch.
he went to the home on the left of the Pokemon center in the survival area
you go to stark mountain and talk to buck (if you already have heatran he will be in reasort area)and he will say there is a volcano thing inside stark mountain and that is is were you will find entai 253689fghhhttghufrheiur8u74856738er