Four Seasons 39421 A/C Expansion Valve - Front

Four Seasons 39421 Expansion Valve Overview

Four Seasons 39421 is a block-type A/C expansion valve for R134A systems. Built from aluminum and engineered to meet or exceed OEM requirements, it regulates refrigerant flow through the evaporator circuit for stable cabin cooling performance.

For buyers searching for an A/C expansion valve for Honda Civic or Toyota Corolla HVAC repair, this Four Seasons Expansion Valve line provides a direct-service replacement format with sealing-washer connections and a 2.000 tonnage rating.

Key Features

• Part number 39421 from Four Seasons Expansion Valve
• Block-type A/C expansion valve for R134A refrigerant
• Aluminum construction with aluminum finish
• Female suction and liquid fittings with sealing washer style connections
• 2 mounting holes for secure installation
• Super heat setting: 8.5
• Meets or exceeds OEM specifications
• Style: without solenoid

Product Details

The Four Seasons 39421 expansion valve meters refrigerant entering the evaporator so the HVAC system can maintain proper cooling balance. Its block-type design, female inlet and outlet fittings, and sealing-washer interfaces support service replacement in R134A air conditioning systems. This part number 39421 is a practical choice when replacing a worn or restricted valve in a Honda Civic, Toyota Corolla, or other vehicle using the same application.

This part cross-references UAC EX10424C for the same application.

Common Problems This Part Can Address

• Weak or inconsistent A/C vent temperatures
• Refrigerant flow restriction at the evaporator
• Compressor cycling caused by improper metering
• HVAC performance loss from a sticking expansion valve
• Cooling imbalance after A/C system service

Installation Notes and Tips

Verify refrigerant type, fitting style, and port sizes before installation. This valve uses female suction and liquid connections with No. 10, No. 12, and No. 8 thread diameters as listed, along with sealing washer style interfaces. Replace any contaminated system components as needed, evacuate the system properly, and recharge with the correct R134A specification after service. Confirm the vehicle application against the original valve layout before final assembly.

Quality Assurance

Four Seasons manufactures HVAC service parts to OE-style standards, and this 39421 expansion valve is listed as meeting or exceeding OEM requirements for the specified application.