Mercedes W169 W245 OM640 CDI Oil Filler Neck Cap A6400100369

Mercedes W169 W245 OM640 CDI Oil Filler Neck Cap is an original lubrication system component designed for OM640 diesel engines in A-Class and B-Class models. This component from the Oil coolers and lines group ensures a tight seal of the oil filler neck, which is essential for the stable operation of the power unit and the cleanliness of the engine bay. It is a practical solution for users seeking factory fitment and predictable performance parameters.

Specifications and technical data

• SKU: A6400100369-2
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6400100369
• Substitutable numbers: A6400100369, A 640 010 03 69
• Category: Engine Oil Coolers & Lines

Purpose and technical function

The oil filler cap in the OM640 engine is responsible for maintaining proper pressure and sealing in the upper part of the lubrication system. A correctly selected component reduces the risk of leaks, contamination entering the oil, and uncontrolled evaporation. In the case of CDI units installed in Mercedes A-Class W169 and B-Class W245, this has a direct impact on engine refinement and the durability of components interacting with the oil.

Benefits of using an original cap

Using a cap dedicated to a specific engine type allows for maintaining factory sealing parameters and fitment with the valve cover. The correct thread profile, diameter, and seal geometry translate into:

• stable oil filler sealing under typical operating conditions,
• reduction of dirt around the valve cover,
• trouble-free installation and removal during service maintenance. For Mercedes users, maintaining structural consistency with other lubrication system components is also important, which promotes predictable engine behavior over the long term.

Application in the lubrication and oil cooling system

Although the oil filler cap is a small element, it works with the entire lubrication circuit, including components from the Oil coolers and lines group. A tight seal helps maintain proper operating conditions for the oil, which then circulates through lubrication channels and components responsible for its cooling. In CDI engines, where oil operates under demanding thermal conditions, the correct cap is one of the factors supporting the stability of the power unit's operating parameters.

Condition, fitment, and installation

The offered item is a salvaged part and is intended for users looking for a solution with factory geometry and fitment for the valve cover in the OM640 engine. Installation of the cap is simple and does not require specialized tools – proper seating and tightening according to service practice, while keeping the socket and the component itself clean, is sufficient. Replacing a worn or leaking cap is recommended especially when signs of oil leakage appear around the filler neck or there are issues with closing it properly.

Technical support and selection of used parts

When selecting used lubrication system components, such as an oil filler cap, it is worth being guided by compatibility with the specific engine type and the actual condition of the part. If you want to better understand when the use of salvaged components is economically and technically justified, as well as how to diagnose oil leaks or other operational symptoms, check out our article on car repairs using used auto parts. 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 oil lines, mounting elements, or components working with the oil circuit, check the available parts in the Mercedes oil coolers and lines category.