Mercedes W168 OM668 Fuel Hose Diesel Fuel Pump Return Line Pipe A6680780381

Mercedes W168 OM668 Fuel Hose Diesel Fuel Pump Return Line Pipe is a fuel system component designed for diesel engines, responsible for the safe return of excess fuel to the tank. Thanks to its precise fit for the Mercedes W168 series design, it ensures stable operation of the injection system and helps maintain proper fuel pressure parameters. It is a practical solution for users looking for a proven, original component from the Lines, Hoses and Pipes group.

Specifications and technical data

• SKU: A6680780381
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6680780381
• Substitutable numbers: A6680780381, A 668 078 03 81
• Fuel type: Diesel
• Category: Hoses, Lines & Pipes

Function and role in the diesel fuel system

The return hose in a Diesel engine is responsible for draining unused fuel from the fuel rail or injectors back to the tank. A correctly selected line:

• stabilizes pressure in the fuel supply system,
• reduces the risk of air entering the system,
• supports smooth injector operation,
• minimizes fuel losses and leaks.

In the case of the Mercedes W168, using a dedicated return hose allows for maintaining the factory operating characteristics of the power unit and avoiding problems typical of ill-fitting replacements.

Construction and fit for Mercedes W168

The presented hose belongs to the Lines, Hoses and Pipes group, which means it has been designed to work in a diesel fuel environment. The construction of the line is adapted to:

• the geometry of the Mercedes W168 engine bay,
• factory mounting points and line routing,
• cooperation with diesel injection system components.

Such a fit reduces stress, twisting, and kinking of the line, which translates into stable operation and a lower risk of leaks in the long term.

Component condition and service application

The offered fuel hose is a used part, which makes it a reasonable choice for an economical repair of the fuel system in older Mercedes W168 models. It is particularly useful in situations where:

• the original line has suffered mechanical damage or abrasion,
• there are fuel leaks in the return area,
• it is necessary to replace several fuel system components during a single service intervention.

Using an original line from the same design group helps maintain system integrity and facilitates the diagnosis of any future faults.

Benefits of using an original return hose

Selecting the right return hose in a diesel engine has a direct impact on vehicle comfort. Using a dedicated line in a Mercedes W168 allows you to:

• maintain correct injection system operating parameters,
• reduce the risk of uncontrolled fuel leaks,
• limit irregularities in starting and idling,
• maintain the factory routing of lines in the engine bay.

For workshops and individual users, this means a more predictable installation process and fewer potential problem points in the future.

Related components and additional technical information

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 supply lines, flexible fuel hoses, or rigid guide pipes, check the available parts in the Mercedes Lines, Hoses and Pipes category.

For users interested in a broader context of operating power units of this brand, including issues related to engine accessories and the injection system, the guide article Reliability under the star sign – how to take care of engine accessories in popular Mercedes-Benz models, which discusses practical tips on selecting and servicing components, may be helpful.