BMW E46 X3 E83 X5 E53 Automatic Expansion Tank Radiator Header 7573781

The BMW E46 E53 E83 Expansion Tank is a cooling system component from the expansion tanks category, designed for BMW models equipped with an automatic transmission. Its original design ensures proper functioning of the cooling system, stable fluid pressure, and safe dissipation of excess engine heat. This is a practical solution for users seeking a proven, used component with factory geometry and fitment.

Specifications and technical data

• SKU: 7573781-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7573781
• Substitutable numbers: 7573781, 17117573781, 7787039, 17137787039, 2247553, 17132247553, 1436413, 17111436413, 335509141, 200315
• Gearbox type: Automatic
• Category: Expansion & Overflow Tanks

Purpose and Compatibility

The presented expansion tank has been designed for BMW E46, E53, and E83 series cars with automatic transmissions. The construction matches the factory solutions used by the manufacturer, which facilitates installation in place of a worn or damaged part without the need for modifications to the system.

By maintaining the original geometry of the connectors and mounting points, the tank works with factory cooling system hoses and standard sensors, ensuring proper fluid circulation and stable operation of the entire system.

Construction and Function in the Cooling System

The expansion tank plays a crucial role in compensating for changes in coolant volume and maintaining the correct fluid level in the system. The properly designed working chamber and flow channels enable:

• monitoring of coolant level under various engine operating conditions,
• stabilization of system pressure,
• safe discharge of excess fluid when temperature rises,
• reduction of the risk of air ingress into the cooling system.

A correctly selected expansion tank helps maintain optimal engine operating temperature, which is important for both engine durability and driving comfort.

Benefits of Using an Original BMW Tank

Using an original expansion tank in BMW E46, E53, and E83 offers a number of practical benefits:

• Factory Fitment – maintaining original mounting points and connections minimizes installation time.
• System Compatibility – the tank works with the standard pump, radiator, and hoses without the need for adaptation.
• Stable Operation in Automatic Transmission Vehicles – adaptation to the specifics of automatic transmission models promotes the maintenance of proper powertrain operating temperature.
• Economical Choice – a used component allows for reduced service costs while maintaining factory construction.

Condition, Verification, and Service Application

The offered tank is a used part, removed from a vehicle, and is designated as a used BMW component. This is a practical solution for users who need to replace a worn or leaking tank and wish to stick with an original part rather than an aftermarket replacement of unknown origin.

The component is suitable for both standard operation and more demanding driving conditions where the cooling system operates under greater load. Replacement of the tank is recommended in case of visible cracks, leaks, problems with maintaining fluid level, or recurring engine overheating warnings.

More Expansion Tanks and Technical Advice

If you are looking for other BMW expansion tanks compatible with various models of this brand, check out our dedicated category: BMW expansion tanks. There you will find a wide selection of cooling system components, making it easier to choose the right solution for your specific engine version.

When planning an upgrade or more extensive work on your car, it's worth exploring the possibilities of using used components safely and cost-effectively. Practical tips can be found in the article: Tuning with Used Parts – How to Gain Performance Without Losing a Fortune, which discusses topics such as component selection and technical condition checks.