I would send it back for a replacement. All my stock BLX have been pushed hard on 6s geared tall. I'm good about checking temps and have never thermaled them beyond 170°F, usually 140-150 ish. Was your mesh OK? Too tight will get hot pretty easily.
@Steveoarrma517 not sure why Arrma gears are all odd number, but certain the material is crap. It's not that uncommon for there to be a tighter spot when checking mesh as tolerances may not always be perfectly concentric with machined gears. I normally spin my spur a full rotation and adjust my mesh to accommodate a tight spot. Also possible the motor shaft or mount could be tweaked. I run mostly 16 tooth or bigger partly because it's easier to get a proper mesh with more teeth and surface contact area. Too tight a mesh is definitely louder like the car is eating itself, but with dogbones and outdrives clanging, these rigs aren't quiet either.