He lives in the house next to the Pokemon Center in I believe the Survival Area. He's only there after you escort him to the magma stone and he takes it.
Hope I've helped!
.:Funkeheap15>.<:.
I think Stark Mountain.
Battle Tower.
you visit buck in survival area talk to buck and go to the cave. Heatran will be there.
you can find buck at the survival area in the house next to the Pokemon center hopes the helps
either 1 or 2 to the left of the Pokemon center
in the Pokemon diamond and pearl versions i know that the heatran (mostly a girl) will be at stark mountain go up there with buck go out talk to buck and his grampa go back up to stark muntain heatran is there
Battle Tower.
Buck lives in the Survival Area in Pokemon Platinum. Buck is part of a quest involving Stark Mountain and Heatran.
he goes to the house near the Pokemon center in the survival area
help buck get to the magma stone then go to the house next to the Pokemon center in the survival area then talk to buck then go to where the magma stone was and heatran will be there
Pearl Sydenstricker Buck.
you go to the survival area and talk to buck he's in one of the houses