Mercedes ML W166 Fuel Injector Leak Pipe Hose Line OM651 Diesel A6510705532

The Mercedes ML W166 Fuel Return Line OM651 Diesel is an original fuel system component designed for OM651 diesel engines in the W166 generation ML model. This specialized line, part of the Lines, Hoses, and Tubes group, is responsible for controlled fuel return, supporting stable injector system operation and proper diesel circulation within the high-pressure unit.

Specifications and technical data

• SKU: A6510705532
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6510705532
• Substitutable numbers: A6510705532, A 651 070 55 32
• Fuel type: Diesel
• Category: Hoses, Lines & Pipes

Purpose and Function in the Fuel System

The fuel return line in the Diesel OM651 engine plays a crucial role in draining excess fuel from the fuel rail or injectors back into the system. A properly functioning component of this type stabilizes pressure in the circuit, reduces the risk of air ingress, and supports uniform injector operation, which translates to smoother engine performance and correct cold and hot start characteristics.

In modern diesel engines like the OM651, the integrity and appropriate cross-section of the return line are vital for maintaining correct fuel pressure parameters and protecting the precision components within the injection system.

Construction and Fit for Mercedes ML W166

The offered line belongs to the Lines, Hoses, and Tubes group and is structurally designed to fit the engine bay architecture of the Mercedes ML W166 with the OM651 unit. Its shape, connection diameters, and branch arrangement are engineered to allow installation at factory mounting points without the need for modifications or adapters.

Original Mercedes origin ensures compliance with factory quality standards, as well as compatibility with factory brackets, clamps, and wiring harness routing within the engine bay. This ensures that the line does not interfere with other components after installation, reducing the risk of abrasion and leaks over the long term.

Condition, Verification, and Service Application

The component is offered as used, which is often a cost-effective solution in workshop practice for repairing fuel systems in vehicles several years old and older. This type of fuel return line can be used as a replacement for a damaged or leaking part, or as a component replaced preventatively during major service work on the diesel engine.

Choosing an original fuel return line for a specific ML W166 model with an OM651 engine helps avoid problems typical of universal fuel hoses, such as mismatched diameters, inadequate material resistance, or incorrect routing in the engine bay.

Benefits of Using an Original Fuel Return Line

• Maintains stable fuel system pressure in the diesel engine.
• Reduces the risk of leaks and air ingress in the fuel supply system.
• Factory-matched to the engine bay geometry in the Mercedes ML W166 with the OM651 unit.
• Compatible with other components of the diesel injection system.
• Supports uniform injector operation and correct engine starting.

System Expansion and Additional Information

If you are planning a comprehensive repair or engine area upgrade for your Mercedes and need other parts from the same group, such as return lines, supply hoses, or fuel tubes, check the available parts in the Mercedes Lines, Hoses, and Tubes category.

For those interested in a broader context of the manufacturer's technical solutions and the evolution of components across car generations, a valuable addition to your knowledge could be the article Evolution of the Mercedes S-Class: From W140 to W222 – Innovations, Model Differences, and Mercedes Auto Parts Over the Years, which discusses, among other things, the brand's approach to designing key vehicle systems.