The Mechanar is the first wing of the Tempest Keep instance. It serves as a base for Pathaleon the Calculator and also generates manacells, which contain an incredible amount of power. It once belonged to the Naaru.
This is the purple crystal building south of the main palace. As you need a flying mount to get inside the instance, it is not possible to run the Mechanar until level 70 (68 for druids). After Patch 2.4, it is now possible to enter the Mechanar via a warlock summoning as an alternative.
One full run with all mobs cleared yields about 1620 reputation with the Sha'tar.
The Mechanar consists of two levels joined by an elevator. The first level has two named elites and one boss. Both named elites must be killed to open the elevator. You must also kill both Gatewatchers to open the Cache of the Legion. The first optional boss (Mechano-Lord Capacitus) has a decent loot table of his own.
On Heroic mode, these first three bosses (prior to Patch 2.3) are known as the Three Free Badges, as the Gatekeepers remain virtually unchanged from regular mode and Mechano-Lord Capacitus becomes a ridiculously easy fight with proper positioning. Moderately geared groups can fight their way through the first floor in less than an hour, even with a wipe or need to retreat. As of Patch 2.3 the Gatekeepers no longer drop a [Badge of Justice] each, instead one is found in the Cache of the Legion.
Both the second optional boss and the end boss of the instance are up the elevator.
Gatewatcher Gyro-Kill and Gatewatcher Iron-Hand are mini-bosses. Each drops a portion of a key which is used to open the Cache of the Legion just before the elevator.
There are currently a number of issues in this instance. They are listed here along with workarounds. These are issues acknowledged in Blizzard posts that are planned to be resolved.
Problem: This client-side issue causes some players to not be able to see the elevator. This occurs on a per-instance basis.
Workaround: If you encounter this problem, the only ways around it are to:
Patch 2.0.12 (4/3/07): The gate at the top of the elevator in The Mechanar will now remain open while attempting the gauntlet and after Pathaleon the Calculator is killed
Problem: Under certain circumstances, the elevator gateway remains closed after the group wipes. This issue is still not fixed as of 7 March, 2007 in patch 2.0.10.
Workaround: The best ways to deal with this are:
Note: GM stated that devs have asked that players not be ported to the other side of the gate after this occurs, as this may cause other problems.
Problem: If attempting to reset the final boss by running towards the elevator, sometimes he may bug, keeping the remainder of the instance inaccessible. When Pathaleon mind-controls the players, they will release and fall under the map. When this happens, the client may be disconnected and will have difficulty getting back on. After this, Pathaleon and his adds will be scattered between several rooms in the back half of the instance, rendering the instance unplayable.
Currently (Patch 2.3.3) there is no known workaround, a GM must be paged to reset the mobs and, occasionally, the players as well.