Mercedes R231 M276 Water Coolant Expansion Overflow Tank Bottle A2315000049

Mercedes R231 M276 Water Coolant Expansion Overflow Tank Bottle is an original cooling system component designed for gasoline engines, ensuring stable operation and safe discharge of excess fluid. Thanks to its precise OEM design, the tank maintains proper system pressure, which supports efficient engine cooling and reduces the risk of overheating. This technical solution is dedicated to users who expect compatibility with the factory installation and predictable performance in daily operation.

Specifications and technical data

• SKU: A2315000049
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2315000049
• Substitutable numbers: A2315000049, A 231 500 00 49
• Fuel type: Petrol
• Category: Expansion & Overflow Tanks

Purpose and function in the cooling system

The presented expansion tank operates within the gasoline engine cooling system, responsible for compensating for fluid volume changes during engine heating and cooling cycles. It allows for the safe collection of excess fluid, stabilizes pressure, and facilitates coolant level monitoring. As a result, the cooling system maintains an appropriate operating reserve, and the engine can run within the optimal temperature range.

Construction and fitment for Mercedes R231 M276

The tank has been designed specifically for the engine bay architecture in models with the M276 unit, which translates into proper hose routing, correct mounting points, and ergonomic service access. The original body geometry ensures:

• secure seating in factory brackets,
• correct positioning of connection ports relative to cooling hoses,
• stable operation even under high thermal loads.

By adhering to the manufacturer's specifications, installation is straightforward, without the need for system modifications or custom mounting hardware.

Technical and operational characteristics

As a component from the Expansion tanks group, this part works with the gasoline engine cooling system, supporting the maintenance of stable operating parameters. The tank's construction is adapted for operation in variable temperature conditions and pressure fluctuations typical of modern engines. The properly shaped working chamber facilitates:

• coolant level monitoring during inspections,
• system bleeding after fluid replacement,
• maintaining fluid reserve during dynamic driving.

Such properties promote stable cooling system operation and reduce the risk of improper fluid circulation in the circuit.

Condition, origin, and service application

The offered tank comes from dismantling and is a used part, making it an attractive cost-effective alternative to new OEM components. It is particularly useful in situations where replacing a damaged or leaking tank is necessary, and the priority is to maintain the original assembly specification. Choosing this solution allows for:

• maintaining the factory cooling system configuration,
• reducing repair costs while maintaining compatibility,
• consistency with other components in the engine bay.

Selection support and upgrade expansion

In the case of extensive service work within the cooling system, it is worth considering simultaneous inspection of hoses, clamps, and other elements interacting with the tank. If you are planning a comprehensive repair or upgrade of the engine area in your Mercedes and need other elements from the same group, such as additional tanks, mounting hardware, or related cooling system components, check the available parts in the Mercedes expansion tanks category.

If you are also interested in improving driving comfort and interior ergonomics during major service work, it is worth checking out the guide on seat upgrades – you can find practical tips in the article Interior metamorphosis: how branded seats from dismantling improve comfort and car value.