Nissens 999231 A/C Expansion Valve

Nissens A/C Expansion Valve 999231

Nissens 999231 is a block-style A/C expansion valve built from aluminum for R134A systems. It regulates refrigerant flow through the evaporator circuit to help maintain stable cabin cooling performance in BMW applications.

Key Features

• Block-type A/C expansion valve for HVAC refrigerant control
• Aluminum construction for corrosion resistance and thermal stability
• Configured for R134A refrigerant systems
• Mounting hardware included
• Includes O-rings and 4 O-rings are listed in the product data
• Liquid inlet and outlet thread diameter: 0.5500
• Suction inlet thread diameter: 0.7900; suction outlet thread diameter: 0.7100

Detailed Description

This Nissens A/C expansion valve, part number 999231, is engineered for BMW HVAC systems that use a block-style refrigerant metering design. By controlling refrigerant delivery into the evaporator, it supports consistent A/C operation in models such as the BMW 525i, 530i, 528i, 535i, 550i, 645Ci, 650i, M5, and M6. Nissens develops thermal management components with a focus on quality and ongoing aftermarket coverage, and this valve follows that approach with aluminum construction and R134A compatibility.

This part cross-references Febi-Bilstein 39222 for the same application.

What This Part Helps Address

• Weak or inconsistent cabin cooling
• Improper refrigerant metering at the evaporator
• A/C performance issues caused by a worn expansion valve
• Refrigerant flow irregularities in R134A systems
• Service replacement needs on BMW HVAC systems

Installation Notes and Tips

Verify the vehicle uses the correct block-style expansion valve and R134A refrigerant system before installation. Inspect the mating surfaces, replace worn seals as needed, and confirm the line thread diameters match the existing HVAC connections. Proper evacuation and recharge procedures are required after A/C service.

Quality Assurance

Nissens positions this component within its thermal management range and manufactures products to consistent aftermarket quality standards. Part number 999231 is built to support reliable HVAC service in the listed BMW applications.