You can find The Mechanar dungeon within Tempest Keep, Netherstorm.
The coordinates are (70.3,68.6)
1. Mechano-Lord Capacitus
Heroic Differences: Polarity Shift changes players energy. Split into 2 groups one negative & one positive charged.
2. Nethermancer Sepethrea
/i Avoid standing in front boss for Dragon Breath. Her weapon is enchanted with frost, has chance to slow players movement. Arcane Blast damages & knocks back player. Raging Flame mobs cast Inferno, move away as damage all nearby.
3. Pathaleon the Calculator
Heroic Differences: Arcane Explosion inflicts arcane damage to players in 30 yards.