In regards to PKMN Platinum, Arcanine cannot be found in the wild. Growlithe, however, can be found on Route 201 and Route 202 when PKMN FireRed version is inserted in the GBA slot.
There is no Arcanine in Pokemon Platinum. You must find a Growlithe and evolve it with a fire stone. You can find Growlithe in Route 201 and 202 with Pokemon FireRed in your GBA slot.
You can find it at route 228 with the poke radar
Route 212 with the poke Radar
route 210 (use poke radar)
Route 210 South (Poke-Radar)
On route 229 with the poke radar(rare)
Mt.cornet use a poke radar (it is rare)
put firered in the gameboy slot and go to route 201. Go through the tall grass until you find a growlithe. Capture it. then evolve it into arcanine.
go to route 209 and use the poke radar
Use your poke radar on route 205 north.
you cheat but try to find them with the poke radar
use the poke radar on route 218 (rare)