Nissens 707300 HVAC Heater Core

Nissens HVAC Heater Core 707300

The Nissens 707300 HVAC heater core is built for direct replacement in select Mazda applications, including the 2014-2021 Mazda 6 and 2014-2018 Mazda 3. It uses aluminum core and tank construction with brazed cooling fins to support efficient heat transfer and consistent cabin heat output.

Key Features

• Aluminum core and aluminum tank construction
• Brazed cooling fins for efficient thermal transfer
• Inlet and outlet pipe diameter: 0.69 in.
• Pipe included: Yes
• Core dimensions: 5.7500 in. H x 10.2800 in. L x 1.3000 in. W
• Built and tested to OE specifications

Product Details

Nissens heater cores are manufactured and tested to OE-level specifications, with life testing that includes vibration, pressure impulse, thermal expansion, corrosion, and burst evaluation. That process helps verify sealing integrity, heating performance, and clean operation. The 707300 is finished for smooth fitment into the HVAC module mounting cassette and is a direct-fit choice for Mazda 6 and Mazda 3 heater core replacement service. This part cross-references APDI 9010718 for the same application.

Common Issues This Part Can Address

• Weak or uneven cabin heat
• Coolant leakage from the heater core area
• Restricted heat transfer from corrosion or internal buildup
• Fitment problems with a worn or damaged original heater core
• HVAC performance loss in Mazda 6 and Mazda 3 heating systems

Installation Notes and Tips

Verify the core dimensions and pipe size before installation to confirm proper fit in the HVAC case. Inspect coolant hoses, seals, and the surrounding HVAC housing during service, and flush the cooling system if contamination or debris is present. Fits 2014-2021 Mazda 6, N/A. Fits 2014-2018 Mazda 3, N/A.

Quality Assurance

Nissens heater cores are produced and tested to OE specifications, with validation steps focused on leakage resistance, thermal durability, and corrosion resistance. The 707300 is designed to fit smoothly into the HVAC module mounting cassette for a clean replacement installation.