How to Replace the Heater Core in a Mazda6

Replacing a Mazda6's heater core is not recommended for those who don't completely know the car's interior. You must remove multiple components, including the steering column and dashboard, in order to reach the core. You'll need another person to help you remove the dash.

Things You'll Need

• Replacement heater core
• Clean containers
• Wrench
• Screwdriver
• Steering wheel puller
• Pliers

Instructions

1. Unplug the Mazda6's negative battery cable. Discharge the air conditioner's refrigerant and drain the engine coolant (use clean containers). Remove the dynamic chamber.

2. Take out the glove box by removing the damper clip, disengaging the stoppers and removing the glove box clips. Remove the console, meter hood, instrument cluster, column cover and lower panel.

3. Detach the steering shaft. Remove the driver air bag from the wheel and the wheel while the tires face straight ahead. Remove the column cover, clock spring and combination switch.

4. Disassemble the dashboard. Remove the A-pillar trim, front scuff plates and side trims, side panels, A/C unit wires, harness connectors. bolts and pins. Have an assistant help remove the dashboard through the driver side door.

5. Disconnect the theft control module and the heater hose from the firewall. Disconnect the block joint type pipes by removing the connection bolt while holding the female side of the block with pliers.

6. Remove the heater core by removing the duct, blower motor, A/C cases, harness, air intake actuator and crank, air filter, resistor or PMW unit, air flow mode system, air mix system and water temperature sensor. Open the heater core cover and remove the core.

7. Install the replacement heater core. Reinstall the heater core, theft control module, dashboard, steering shaft and glove box. Connect the battery cable, refill the cooling system and recharge the air conditioner.

Tips & Warnings

• You must adjust the clock spring when reconnecting it. With the tires straight ahead, turn the spring clockwise until it stops, then turn it counterclockwise two and three-quarter turns. Align the marks, confirm that the tilt lever locked, then tighten the steering shaft bolt A, nut B and nut C.