Mercedes C218 Expansion Tank Breather Hose A2125013625

Mercedes C218 Expansion Tank Breather Hose is an original cooling system component designed for installation in the rear section of the vehicle. Thanks to its factory geometry and precise fit for the OM651 unit, it ensures stable coolant flow and proper integration with other system components. This is a practical solution for users looking for a proven water hose for their W212 generation Mercedes E-Class.

Specifications and technical data

• SKU: A2125013625
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2125013625
• Substitutable numbers: A2125013625, A 212 501 36 25
• Location on the vehicle: Rear
• Category: Hoses, Lines & Pipes

Function and application of the water hose

The described water hose operates in the rear area of the vehicle, where it is responsible for transporting coolant between the components of the OM651 diesel engine cooling system. A properly selected water hose helps maintain a stable operating temperature for the power unit, which translates into its durability and consistent performance characteristics.

Thanks to a design tailored to the architecture of the Mercedes W212, the hose maintains the correct positioning relative to the body and sub-assemblies, minimizing the risk of chafing, kinking, or uncontrolled stress during operation.

Benefits of using an original Mercedes hose

Using an original water hose in the cooling system provides a number of technical benefits:

• factory fit for the OM651 engine and the rear vehicle structure,
• maintenance of the designed diameter and coolant flow cross-section,
• proper routing of the hose relative to mounts and covers,
• reduction of the risk of leaks resulting from poorly fitted aftermarket replacements,
• consistency with other components of the Mercedes W212 cooling system.

For the user, this means more predictable cooling system operation and easier diagnostics during potential inspections or service.

Installation and operational characteristics

The water hose designed for the rear of the vehicle is engineered for installation at factory mounting points, which facilitates the mechanic's work and reduces replacement time. The properly selected length and shape of the hose help avoid incorrect routing, which could cause local overheating or restricted fluid flow.

As an item in the Hoses, pipes, and tubes category, this part works with other cooling system components, such as the radiator, connectors, fittings, or other hose sections. Proper selection of this element is particularly important in diesel engines, where stable heat dissipation is crucial for the operation of the power unit.

Product condition and service application

The offered water hose is a used item, making it an attractive service solution in situations where an optimal cost-to-functionality ratio is important. This type of part is suitable for both standard replacement of a worn hose and for post-accident repairs or cooling system upgrades in a Mercedes W212 with an OM651 engine.

Choosing an original salvaged hose allows you to maintain the structural integrity of the vehicle while reducing costs compared to new parts, all while maintaining the correct coolant flow parameters.

Related Mercedes cooling system components

If you are planning a comprehensive repair or upgrade of the cooling system area in your Mercedes and need other items from the same group, such as additional water hoses, flexible hoses, or rigid pipes for coolant transport, check out the available parts in the Mercedes hoses, pipes, and tubes category.

When planning broader service work, it is also worth checking out practical tips regarding the selection of used powertrain components and accessories – you can find helpful information in the article Used transmission – when is it worth it and what you need to remember, which discusses key aspects of assessing technical condition and the cost-effectiveness of purchasing parts from the secondary market.