Mercedes-Benz C-Class W204 Coolant Expansion Tank Reservoir Bottle A2045000049

Mercedes-Benz C-Class W204 Coolant Expansion Tank Reservoir Bottle is an original cooling system component designed for W204 series models. Thanks to its factory design, it ensures proper coolant volume compensation and stable engine operating conditions, which translates into safe and predictable vehicle operation.

Specifications and technical data

• SKU: A2045000049
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2045000049
• Substitutable numbers: A2045000049, A 204 500 00 49
• Category: Expansion & Overflow Tanks

Function and role in the cooling system

The expansion tank in the Mercedes W204 is responsible for maintaining the correct coolant level and compensating for pressure changes during engine heating and cooling. A properly selected component from this group:

• stabilizes pressure in the cooling system,
• enables safe discharge of excess fluid,
• facilitates monitoring of the working medium level,
• reduces the risk of engine overheating.

As a result, the cooling system operates under predictable conditions, and the engine maintains proper thermal parameters in various driving modes.

Compatibility and fit for Mercedes W204

The offered reservoir has been designed specifically for the W204 platform, which means factory mounting points and correct connections for cooling system hoses. The original housing geometry facilitates installation in the engine bay without the need for modifications, and the matched tank capacity supports proper fluid circulation.

By maintaining the manufacturer's specifications, the component works seamlessly with the existing cooling installation, minimizing the risk of leaks and system venting issues.

Characteristics of the used component

The presented expansion tank is a secondary market part, which allows for an economical repair of the cooling system while maintaining the original design. This type of component is particularly beneficial in the case of:

• cracks or leaks in the existing tank,
• corrosion or wear of the connection ports,
• problems with maintaining a stable coolant level.

Choosing an original, used component allows you to maintain technical consistency with other Mercedes sub-assemblies, which is important for long-term vehicle operation.

Benefits of using an original expansion tank

Compared to replacements of unknown origin, the original expansion tank for the Mercedes W204 provides:

• factory fit for the cooling system,
• compliance with engine and accessory operating parameters,
• easier diagnostics of potential leaks,
• consistency with the manufacturer's service documentation.

Therefore, it is a solution particularly recommended for repairs where technical correctness and predictable system behavior in the long term are prioritized.

Expansion and service of the Mercedes cooling system

If you are planning a comprehensive repair or upgrade of the cooling system area in your Mercedes and need other components from the same group, such as coolant hoses, pressure caps, or additional reservoirs, check the available parts in the Mercedes expansion tanks category.

To deepen your knowledge on diagnostics and component selection according to manufacturer markings and the principles of operating systems with working fluids, it is worth reading the article Fuel system – injectors, pumps, and fuel tank: maintenance and regeneration, which discusses a practical approach to working with vehicle sub-assemblies, OEM numbering, and service procedures.