Four Seasons 39678 A/C Expansion Valve

Four Seasons 39678 Expansion Valve for Hyundai Sonata

The Four Seasons 39678 A/C expansion valve is a block-type HVAC flow restrictor built for precise refrigerant control in the air conditioning system. It is listed for 2020-2023 Hyundai Sonata applications and uses aluminum construction with R134A refrigerant service.

Key Features

• Block-type A/C expansion valve for HVAC refrigerant metering
• Aluminum body for OE-style fit and serviceability
• R134A refrigerant type
• Liquid inlet: No. 6 O-ring
• Liquid outlet: No. 10 O-ring
• Suction inlet: No. 12 O-ring
• Suction outlet: No. 12 O-ring
• Meets or exceeds OEM requirements
• Mounting hardware included
• Super heat rating: -9.0; tonnage: 1.0

Product Details

Four Seasons Expansion Valve 39678 is part of the brand’s expansion valve line, backed by more than 50 years of mobile A/C experience. The design is engineered and tested for dependable operation in the HVAC system, helping regulate refrigerant flow through the evaporator circuit. For drivers and technicians servicing a Hyundai Sonata A/C system, this valve provides the correct block-style configuration with O-ring connections and the specified port sizes for a direct replacement approach.

This part cross-references Febi-Bilstein 39678 for the same application.

What It Helps Fix

• Inconsistent cabin cooling in the Hyundai Sonata
• Incorrect refrigerant metering at the evaporator
• A/C performance loss caused by a worn or restricted expansion valve
• Temperature fluctuations from improper superheat control
• Leak concerns at aging O-ring style A/C connections

Installation Notes

Verify the vehicle uses the listed R134A system and block-type valve configuration before installation. Inspect the mating surfaces, O-rings, and refrigerant lines for wear or contamination, and replace damaged seals as needed during service. Confirm the liquid and suction port sizes match the original setup on the 2020-2023 Hyundai Sonata before recharging the system.

Quality Assurance

Four Seasons states that its HVAC components are engineered and tested for years of trouble-free operation. The 39678 expansion valve is listed as meeting or exceeding OEM requirements for the specified application.