Engine Coolant Temperature (ECT) Sensor Removal/Installation

Remove the battery cover.
Disconnect the negative battery cable. (See BATTERY REMOVAL/INSTALLATION [LF] ).
Drain the engine coolant from the radiator. (See ENGINE COOLANT REPLACEMENT ).
Remove the service hole cover.
1. Remove the suspension tower bar (joint), (right side) and (left side). (See FRONT SUSPENSION TOWER BAR REMOVAL/INSTALLATION ).
2. Remove the wiper arm. (See WIPER ARM AND BLADE REMOVAL/INSTALLATION ).
3. Remove the cowl grille. (See COWL GRILLE REMOVAL/INSTALLATION ).
4. Remove the side cowl grille. (See SIDE COWL GRILLE REMOVAL/INSTALLATION ).
5. Move the cooler pipe No. 3 and heater pipe slightly out of the way.
  
  Fig 1: Identifying Heater Pipe And Cooler Pipe No. 3
  Courtesy of MAZDA MOTORS CORP.
6. Remove the service hole cover.
  
  Fig 2: Service Hole Cover With Torque Specifications
  Courtesy of MAZDA MOTORS CORP.
Disconnect the heater hose and move the heater hose slightly out of the way.
Disconnect the ECT sensor connector.

Fig 3: Identifying Heater Hose
Courtesy of MAZDA MOTORS CORP.
Remove the ECT sensor.
NOTE:
- Put the double nut together and install the torque wrench. (See SERVICE CAUTIONS ).
Fig 4: Identifying ECT Sensor
Courtesy of MAZDA MOTORS CORP.
Install in the reverse order of removal.
ECT sensor tightening torque

10-14 N.m {1.1-1.4 kgf.m, 7.4-10.3 ft.lbf}

Fig 5: Installing ECT Sensor
Courtesy of MAZDA MOTORS CORP.