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: Hazardous Driving
WARNING Be extremely careful if it is necessary to downshift on slippery surfaces: Downshifting into lower gear while driving on slippery surfaces is dangerous. The sudden change in tire speed could cause the tires to skid. This could lead to loss of vehicle control and an accident. When dri ...

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 ...