Nissens 999233 A/C Expansion Valve - Front

Nissens A/C Expansion Valve for Mercedes-Benz

The Nissens 999233 A/C expansion valve is a block-style HVAC flow restrictor built from aluminum for R134A air conditioning systems. It helps regulate refrigerant flow through the evaporator circuit, supporting stable cabin cooling in Mercedes-Benz applications that require precise metering.

Compatible with a wide range of Mercedes-Benz models, including G550, Sprinter 2500, S550, C300, E350, and SL550 applications, this part number 999233 is a direct-fit service component for many front-mounted and N/A-position HVAC systems.

Key Features

• Aluminum construction for HVAC durability
• Block-style A/C expansion valve design
• Configured for R134A refrigerant systems
• Includes mounting hardware and O-rings
• O-ring seals and hardware support a cleaner service installation
• Cross-references Four Seasons 39211 and UAC EX10248C for the same application

Product Details

Nissens develops thermal management components with a focus on aftermarket fit and function, and the 999233 expansion valve reflects that approach in a service-ready HVAC control part. It is used to meter refrigerant entering the evaporator, which is critical for maintaining proper system pressure balance and consistent vent temperatures. This part number 999233 is listed across numerous Mercedes-Benz platforms, including Mercedes-Benz G550, Sprinter 3500, and S63 AMG applications.

Vehicle coverage includes 2000-2018 Mercedes-Benz models, with fitment spanning front and N/A positions depending on the application. For Mercedes-Benz Sprinter 2500 front A/C service, as well as Mercedes-Benz S550 front HVAC repairs, this valve supports OE-style replacement needs without changing the system’s refrigerant type.

What It Helps Address

• Weak or inconsistent cabin cooling
• Incorrect refrigerant metering at the evaporator
• HVAC pressure imbalance in the A/C circuit
• Expansion valve leakage or restriction
• Service replacement on Mercedes-Benz A/C systems using R134A

Installation Notes

Verify refrigerant type, port orientation, and vehicle-specific fitment before installation. Replace the O-rings during service and confirm the mounting surfaces are clean and free of debris. This valve is listed for multiple Mercedes-Benz platforms, so match the application carefully to the vehicle’s HVAC layout, especially on models with front-position fitment or auxiliary A/C exclusions.

Quality Assurance

Nissens positions this component within its Genuine Nissens Quality standard, with development and manufacturing focused on thermal system performance and aftermarket reliability. The part is built to support service work on Mercedes-Benz HVAC systems where accurate refrigerant control is required.