Nissens 999378 A/C Expansion Valve - Front

Nissens A/C Expansion Valve for BMW HVAC Service

Nissens part 999378 is an aluminum A/C expansion valve for BMW climate control systems using R134A refrigerant. It is built for precise refrigerant metering in front HVAC applications and is listed for a wide range of BMW 5 Series, 6 Series, 7 Series, and M models.

Key Features

• Aluminum construction for HVAC durability
• R134A refrigerant type
• Block-style A/C expansion valve design
• O-rings included; 4 O-rings listed
• Liquid and suction fitting thread dimensions listed for application matching
• Direct-fit coverage for multiple BMW models, including 640i, 650i, 740i, 750i, and M5

Product Details

This Nissens A/C expansion valve, part number 999378, regulates refrigerant flow into the evaporator so the HVAC system can maintain proper cooling performance. It is specified for BMW vehicles such as the 2012-2018 BMW 640i, 2011-2016 BMW 550i, 2011-2015 BMW 740Li, and 2013-2016 BMW M5, with additional coverage across other BMW Gran Coupe, GT, and xDrive applications. For buyers searching BMW 640i Gran Coupe A/C expansion valve, BMW 750Li front HVAC valve, or BMW M6 climate control replacement, this part number 999378 is the relevant reference.

Nissens develops thermal management components with a focus on aftermarket fit and material quality. This part cross-references BMW 64119159803 for the same application.

Common Problems This Part Can Address

• Weak or inconsistent cabin cooling
• Incorrect refrigerant metering at the evaporator
• HVAC performance loss after A/C service
• Restricted refrigerant flow in the expansion valve circuit
• Leak-related service replacement when the valve and seals are renewed

Installation Notes and Tips

Verify the vehicle’s refrigerant system uses R134A before installation. Match the valve to the BMW model, year, and HVAC position shown in the fitment list, especially on front-mounted applications such as 740Li, 750Li, 760Li, and ActiveHybrid 7 models. Confirm the inlet and outlet fitting dimensions against the original part before assembly, and replace the O-rings with clean, properly lubricated seals during service. Evacuate and recharge the system according to BMW HVAC procedures after installation.

Quality Assurance

Nissens manufactures thermal and engine efficiency components to consistent aftermarket standards and develops new product categories as vehicle technology changes. Part number 999378 is produced as a Genuine Nissens Quality component for BMW A/C service applications.