Diagnostic procedure
Mazda 6 Service Manual: Service cautions
HANDLING INSUFFICIENT REFRIGERANT LEVEL
If an insufficient refrigerant level is detected at troubleshooting,
do not charge (add) the refrigerant. Because an accurate amount of
refrigerant cannot be determined from the pressure indicated on the manifold
gauge, never charge the refrigeran ...
Mazda 6 Service Manual: Heater core inspection
1. Remove the A/C unit. (See A/C UNIT REMOVAL/INSTALLATION.)
2. Remove the heater core from the A/C unit.
3. Inspect for cracks, damage, and coolant leakage.
If any problems are found, replace the heater core.
4. Inspect for bent fins.
If any are bent, use a flathead screwdriver to stra ...