Four Seasons 39645 A/C Expansion Valve

Four Seasons 39645 Expansion Valve

The Four Seasons 39645 expansion valve is a block-type A/C flow restrictor built for R134A and R1234YF systems. It uses an aluminum body with sealing-washer connections and meets or exceeds OEM requirements for a direct-fit HVAC repair on select Chevrolet and GMC trucks.

Four Seasons Expansion Valve products are backed by more than 50 years of mobile A/C experience, with engineering and testing focused on dependable operation in demanding vehicle HVAC systems.

Key Features

• Block-type A/C expansion valve for controlled refrigerant flow
• Aluminum construction for HVAC service applications
• Works with R134A and R1234YF refrigerant systems
• Sealing-washer inlet and outlet connections
• Meets or exceeds OEM specifications
• Mounting hardware included
• Style: without solenoid
• Liquid inlet: No. 6; liquid outlet: No. 8
• Suction inlet: No. 10; suction outlet: No. 12
• Super heat: -7.000; tonnage: 1

Product Details

Four Seasons 39645 is an A/C expansion valve designed for precise refrigerant metering in compatible Chevrolet Silverado and GMC Sierra HVAC systems. The aluminum block design and sealing-washer ports support serviceable, OE-style replacement in trucks that use this configuration. This part cross-references Global Parts Distributors LLC 3411993 for the same application.

Common A/C Problems It Can Address

• Inconsistent cabin cooling from restricted refrigerant control
• Warm air from the vents when the A/C system is charged
• Erratic evaporator performance caused by a worn expansion valve
• Pressure imbalance in the HVAC system
• Reduced cooling output in Chevrolet Silverado and GMC Sierra applications

Installation Notes

• Verify refrigerant type before service: R134A or R1234YF.
• Confirm port sizes and sealing-washer connections match the vehicle’s HVAC layout.
• Inspect the system for contamination, leaks, and related component wear before installation.
• Use proper A/C service procedures and evacuate/recharge the system to specification after replacement.
• Confirm fitment for the exact Silverado or Sierra model year and trim before ordering.

Quality Assurance

Four Seasons engineers and tests its HVAC components for long service life and OE-level performance. Part number 39645 is built to meet or exceed OEM requirements for select Chevrolet Silverado, Chevrolet Cheyenne, and GMC Sierra applications.

Compatible With 2019-2024 Chevrolet Cheyenne, 2019-2024 Chevrolet Silverado 1500, 2020-2024 Chevrolet Silverado 2500 HD, 2020-2024 Chevrolet Silverado 3500 HD, 2019-2024 GMC Sierra 1500, 2020-2023 GMC Sierra 2500 HD, 2020-2023 GMC Sierra 3500 HD, 2022 Chevrolet Silverado 1500 LTD, 2022 GMC Sierra 1500 Limited, 2019 GMC Sierra 1500 Limited, and 2020-2021 GMC Sierra.