Mazda 6 Service Manual: No.20 noise occurs at idle when vehicle is stopped in all positions/ranges

No.19 excessive shift shock on torque converter clutch (tcc)

No.21 noise occurs at idle when vehicle is stopped in d, s, l ranges, or in r position

Other materials:

Mazda 6 Service Manual: Operating Tips for OGG
OGG is the audio compression format for Xiph. Org Foundation. Audio data can be created and stored at a higher compression ratio than MP3. This unit plays files with the extension (.ogg) as OGG files. CAUTION Do not use an audio file extension on files other than audio files. In addition, do n ...

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 ...