Four Seasons 39121 A/C Expansion Valve - Rear

Rear A/C Expansion Valve for Toyota Sienna

Four Seasons 39121 is a brass TXV A/C expansion valve for R134A systems. It regulates refrigerant flow at the rear HVAC circuit to help maintain proper evaporator performance in the Toyota Sienna.

Compatible with 1998-2003 Toyota Sienna rear A/C applications, including models with two sliding doors for 1998-2000. This Four Seasons Expansion Valve line is built for direct replacement service in rear climate control systems.

Key Features

• Brass construction
• TXV design for refrigerant metering
• Configured for R134A refrigerant systems
• Rear position application
• Four Seasons part number 39121

Detailed Description

Four Seasons 39121 is an A/C expansion valve used to control refrigerant delivery into the rear evaporator on select Toyota Sienna models. By metering refrigerant flow, the valve helps the HVAC system maintain stable cooling performance and proper evaporator operation. This part cross-references UAC EX10118C for the same application.

Fits 1998-2000 Toyota Sienna, rear, w/ 2 Sliding Doors; Expansion Valve. Fits 2001-2003 Toyota Sienna, rear, Expansion Valve. Search terms such as Toyota Sienna rear expansion valve, R134A TXV valve, and Four Seasons 39121 Toyota Sienna rear A/C valve match this application.

What It Helps Address

• Weak rear A/C cooling
• Irregular refrigerant flow at the rear evaporator
• HVAC performance loss from a restricted or worn valve
• Temperature control issues in the rear cabin
• Service replacement for a leaking or sticking expansion valve

Installation Notes and Quality

Install the valve in the rear HVAC circuit and verify the system is properly evacuated and charged with R134A refrigerant after service. Confirm the vehicle year, rear position, and 1998-2000 two-sliding-door configuration before ordering. Four Seasons 39121 is identified for the listed Toyota Sienna applications and is supported by the brand’s HVAC replacement part catalog.