Mercedes W212 W218 Fuel Tank Pipe Hose Line Return Flow OM642 OM651 A2124701664

Mercedes W212 W218 Fuel Tank Pipe Hose Line Return Flow is an original fuel system component, designed specifically for E-Class and CLS models. Thanks to its factory geometry and precise fit for diesel engines, it ensures stable fuel flow in the return circuit and supports the proper operation of the injection system under demanding operating conditions.

Specifications and technical data

• SKU: A2124701664
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2124701664
• Substitutable numbers: A2124701664, A 212 470 16 64
• Part type: Line
• Category: Hoses, Lines & Pipes

Purpose and function in the fuel system

The offered hose belongs to the Pipes, hoses and lines category and is responsible for returning fuel from the fuel rail and auxiliary components to the tank in Mercedes E-Class (W212) and CLS (W218) vehicles with OM642 and OM651 diesel engines. A correctly selected return hose:

• stabilizes pressure in the common rail supply system,
• reduces the risk of air entering the fuel system,
• supports smooth injector operation under variable engine loads,
• minimizes fuel losses resulting from leaks or improper flow. Thanks to its factory fit for the specific architecture of OM642 and OM651 engines, the hose maintains proper routing in the engine bay, which facilitates service and reduces the risk of abrasion against adjacent components.

Construction, fitment and installation

The fuel return hose was designed by Mercedes as an OEM part, which means full compatibility with factory mounting points and quick-connectors used in the fuel system of these units. The hose design includes:

• appropriately selected internal diameter to maintain proper return flow,
• a shape adapted for routing along the body and chassis components,
• connectors prepared for installation without the need for system modifications. This type of hose is particularly important during work related to the injection system, fuel tank replacement, or engine accessory upgrades, where maintaining factory-grade sealing and resistance to operating pressure is required.

Component condition and service application

The offered hose is a used original component, which in practice means it retains factory specifications while offering an attractive price compared to a new part. This type of component is a preferred choice in situations where:

• the existing hose has suffered mechanical damage (cracks, abrasion, leaks),
• replacement is necessary after bodywork repairs or chassis intervention,
• the priority is to maintain original geometry and compatibility with the Mercedes fuel system. Before installation, a standard visual inspection and a leak test after installation in the vehicle are recommended, in accordance with the manufacturer's service procedures.

Benefits of using an original fuel return hose

Using an original return hose in OM642 and OM651 engines translates into a number of practical service and operational benefits:

• Factory fit – no need for modifications, cutting, or adapting universal hoses.
• Stable injection system operation – proper fuel return reduces pressure fluctuations and supports smooth engine operation.
• Operational safety – a properly routed hose reduces the risk of fuel leaks in areas exposed to high temperatures or mechanical damage.
• Consistency with other system components – the hose works with factory connectors, brackets, and covers used in the given model.

Expanding Mercedes fuel system service

If you are planning a comprehensive repair or upgrade of the fuel system area in your Mercedes and need other components from the same group, such as supply lines, flexible fuel hoses, or rigid pipes leading to the tank, check out the available parts in the Mercedes Pipes, hoses and lines category. If you want to better plan the service of engine accessories in popular C-Class and E-Class models and understand the relationships between fuel lines, injectors, and timing, it is worth checking out our service guide: Reliability under the star sign – how to maintain engine accessories in popular Mercedes-Benz C-Class and E-Class models?