Mercedes W203 W210 W211 Radiator Expansion Tank Cap A2105010715

Mercedes W203 W210 W211 Radiator Expansion Tank Cap is an original cooling system component designed for selected Mercedes C-Class and E-Class models. It ensures a tight seal for the expansion tank, stabilizing the cooling system's operating parameters and supporting safe engine operation. Thanks to its factory origin, the cap is precisely matched to the tank's design, which facilitates installation and reduces the risk of leaks.

Specifications and technical data

• SKU: A2105010715
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2105010715
• Substitutable numbers: A2105010715, A 2105010715, A 210 501 07 15
• Category: Caps

Purpose and technical function

The presented cap is a cooling system component responsible for maintaining the correct pressure in the radiator expansion tank. Proper operating pressure affects the boiling point of the coolant, and thus the stable operation of the power unit under a wide range of loads. Using an original Mercedes component minimizes the risk of overheating, leaks, and uncontrolled drops in fluid levels.

In W203, W210, and W211 series vehicles, the expansion tank cap is a wear item that may lose its sealing properties over time. Replacing it with a functional, factory-made cap allows you to restore the correct cooling system operating parameters without the need to interfere with other components.

Construction and fitment for Mercedes models

The original design of the cap ensures compatibility with factory expansion tanks used in Mercedes W203, W210, and W211 models. The shape, thread profile, and contact surfaces are designed for the specific geometry of the tank, which translates into secure seating and consistent sealing after every tightening.

The element belongs to the Covers group, meaning it serves a closing and protective function – it secures the tank's service opening against external contaminants and prevents uncontrolled coolant leakage. Thanks to the use of appropriate materials, the cap is resistant to typical cooling system operating temperatures and contact with operating fluids intended for these models.

Condition, origin, and benefits of choosing a used part

The offered cap comes from disassembly and is marked as a used original Mercedes part. This type of component, provided the sealing mechanism is functional, represents an economical solution compared to purchasing a new part, while maintaining factory fitment and performance characteristics.

Choosing a used expansion tank cap is also real support for the circular economy – reusing functional components reduces waste and raw material consumption. If you want to learn more about the advantages of this approach, it is worth reading the article Circular economy in your garage – how choosing used parts from disassembly really supports environmental protection and your wallet?, which describes the practical benefits of installing used components.

Why it is worth using an original cap in the cooling system

Using a factory cap in a Mercedes cooling system brings a number of technical benefits:

• Stable operating pressure – a properly functioning cap helps maintain the correct pressure in the tank, which translates into predictable cooling system behavior.
• Better sealing – the fit to the tank's geometry reduces the risk of micro-leaks and coolant evaporation.
• Compatibility with Mercedes design – no modifications required; the cap works with factory mounts and threads.
• Economical repair – replacing just the cap is often enough to eliminate problems with fluid loss or unstable engine operating temperatures.

Expanding the scope of service work

When working on the cooling system, it is worth paying attention to other elements in its vicinity, such as hoses, clamps, or additional covers. If you are planning a comprehensive repair or upgrade of the engine bay area in your Mercedes and need other elements from the same group, such as covers, caps, or additional trims, check the available parts in the Mercedes Covers category.