One Stop Solutions 99078 HVAC Heater Core

HVAC Heater Core for Toyota and Lexus Applications

Replace a leaking or restricted heater core with One Stop Solutions part number 99078. This HVAC heater core is listed for select Toyota and Lexus models, including the Toyota 4Runner, Toyota FJ Cruiser, and Lexus GX470, covering model years from 2003 through 2014.

• Direct-fit HVAC heater core for listed Toyota and Lexus applications
• Fits 2007-2014 Toyota FJ Cruiser, N/A
• Fits 2003-2009 Lexus GX470, N/A
• Fits 2003-2009 Toyota 4Runner, N/A
• Cross-references Four Seasons 98028 for the same application
• Cross-references 399991 for the same application

Product Details

One Stop Solutions 99078 is an HVAC heater core used in the vehicle heating system to transfer engine heat into the cabin through the heater box. It is listed for Toyota 4Runner, Toyota FJ Cruiser, and Lexus GX470 applications, making it a focused replacement option for owners servicing the factory heating system on these platforms.

Common Heater Core Issues

• Loss of cabin heat
• Coolant odor inside the vehicle
• Fogging or film on the windshield from heater core leakage
• Coolant loss with no visible external leak
• Uneven or weak heat output from the HVAC system

Installation Notes

Verify the vehicle year, make, and model before installation. Heater core replacement typically requires access through the HVAC case, so compare the original unit and hose connections before reassembly. Inspect related cooling system components and flush the system if contamination is present.

Quality Assurance

This part is identified by One Stop Solutions part number 99078 and is cataloged for the listed Toyota and Lexus fitments. Confirm application details against the vehicle before purchase to ensure proper HVAC service.