Intake Manifold Removal Note

Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT .)
Disconnect the following parts:
1. Upper radiator hose
2. Lower radiator hose
3. Two water hose from the thermostat component
4. Thermostat component side of the water inlet pipe which is under the intake manifold
  
  Fig 1: Intake Manifold Components
  Courtesy of MAZDA MOTORS CORP.
Remove the intake manifold and thermostat component as a single unit
Remove the thermostat component from the intake manifold.

Fig 2: Thermostat Component And Intake Manifold With Torque Specifications
Courtesy of MAZDA MOTORS CORP.