All doors lock automatically when the lock side is pressed. They unlock when the unlock side is pressed.
Driver's door

Front passenger's door

To lock all the doors from an open front door, press the lock side of the door lock switch and then close the door.
NOTE
When locking the doors this way, be careful not to leave the key inside the vehicle.
Locking, Unlocking with Transmitter
Auto Lock/Unlock FunctionMazda 6 Owners Manual: Thermostat
THERMOSTAT REMOVAL/INSTALLATION
1. Remove the plug hole plate.
2. Disconnect the negative battery cable.
3. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS.)
4. Remove the drive belt. (See DRIVE BELT REPLACEMENT.)
5. Remove the washer tank.
6. Remove the P/S oil pump.
Note
...
Mazda 6 Owners Manual: Engine disassembly/assembly
1. Disconnect the engine and automatic transaxle. (ATX) (See AUTOMATIC
TRANSAXLE REMOVAL/INSTALLATION.)
2. Disconnect the engine and manual transaxle. (MTX) (See MANUAL TRANSAXLE
REMOVAL/INSTALLATION.)
3. Remove the intake-air system. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
4. Remove ...