Radiator Expansion Tank BMW X3 F25 X4 F26 Overflow Tank Bottle 7823544

Visual condition of the part

The product shows signs of use visible in the photos.

Radiator Expansion Tank BMW X3 F25 X4 F26 Overflow Tank Bottle is an original cooling system component from the Expansion tanks group, designed for use in BMW vehicles. Thanks to its factory design, it ensures proper cooling system operation, pressure stabilization, and safe discharge of excess operating fluid.

Specifications and technical data

• SKU: 7823544-2
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7823544
• Substitutable numbers: 7823544, 17137823544, 8616418, 17138616418, 7639464, 17137639464
• Category: Expansion & Overflow Tanks

Purpose and function in the cooling system

The presented expansion tank has been designed as a cooling system component for BMW X3 F25 and X4 F26 models. It is responsible for compensating for coolant volume changes, maintaining a stable fluid level, and controlling operating pressure throughout the circuit. A correctly selected tank helps reduce the risk of engine overheating, hose leaks, and uncontrolled fluid loss.

Thanks to a design compliant with the manufacturer's standards, the tank works with factory sensors and hoses, which facilitates diagnostics and subsequent maintenance. This solution is particularly beneficial for repairs where maintaining the original characteristics of the cooling system is important.

Construction and fitment for BMW X3 F25 / X4 F26

The discussed expansion tank is an OEM component, prepared for installation in the engine bay of BMW X3 F25 and X4 F26 series vehicles. The body shape, nozzle placement, and mounting points are adapted to the factory layout of hoses and brackets, allowing for precise seating of the part without the need for modifications. Such fitment translates into stable mounting, reduced vibration, and proper coolant flow.

The element has an assigned OEM part number and associated interchangeable numbers, which facilitates compatibility verification via manufacturer catalogs or the VIN. This allows for an informed selection of the tank for a specific vehicle configuration, minimizing the risk of installing an incorrect component.

Benefits of using an original expansion tank

Using an original expansion tank in a BMW X3 F25 or X4 F26 brings a number of practical operational benefits:

• maintenance of factory cooling system operating parameters,
• secure fitment to existing hoses, brackets, and sensors,
• easier diagnostics of potential faults thanks to compliance with service documentation,
• reduction of the risk of leaks resulting from imprecise fitment.

For the user, this means a more stable engine operating temperature, less load on other cooling system components, and more predictable vehicle behavior in urban and highway conditions. For service centers and workshops, installing an original tank shortens repair time and simplifies inspection procedures.

Part condition and installation aspects

The offered expansion tank is a used part, which allows for economical cooling system repair while maintaining the manufacturer's original specifications. This type of solution is often chosen for comprehensive vehicle repairs, where both technical compliance and rational operating costs are important.

Before installation, a standard service procedure is recommended: checking hose tightness, verifying the condition of the pressure cap, and bleeding the system after filling it with fresh coolant. Properly performed installation and system bleeding allow you to fully utilize the advantages of the original tank and ensure stable engine operation across a wide range of loads.

Cooling system expansion in BMW – Expansion tanks

If you are planning a comprehensive repair or upgrade of the cooling system area in your BMW and need other elements from the same group, such as additional tanks, mounting elements, or related components, check the available parts in the BMW Expansion tanks category.

For users interested in a broader perspective on issues related to the operation and diagnostics of vehicle subassemblies, materials discussing the construction and maintenance of fuel systems and cooperating components may be useful – it is worth reading the article Fuel system – injectors, pumps, and fuel tank: maintenance and regeneration, which organizes service knowledge and facilitates the planning of workshop work.