Volkswagen Passat B7 Fuel Tank Filler Cap Screw Diesel 3AA201550L

Volkswagen Passat B7 Fuel Tank Filler Cap Screw Diesel is an original fuel system component designed to secure the fuel filler neck in diesel-powered vehicles. Thanks to its precise fit to the filler socket and robust construction, the cap ensures a tight seal, supporting the proper operation of the fuel system and reducing the risk of contaminants entering the tank. This is a practical solution for users who expect proven, factory-spec geometry and secure fastening for their Passat B7.

Specifications and technical data

• SKU: 3AA201550L-1
• Mark: Volkswagen
• Condition: Used
• OEM Part Number: 3AA201550L
• Substitutable numbers: 3AA201550L, 3AA 201 550 L
• Fuel type: Diesel
• Category: Fuel Tanks & Filler Necks

Purpose and function in the fuel system

The presented cap belongs to the Fuel tanks and filler pipes category and is responsible for physically sealing the filler neck in a diesel-powered vehicle. The screw-on design ensures a stable fit on the filler thread, which limits fuel evaporation and minimizes the risk of water, dust, or other contaminants entering the tank. A properly selected cap is essential for maintaining the integrity of the fuel system, and thus for the correct operation of the pump, injectors, and the entire diesel engine supply installation.

Construction and functional features

The fuel tank filler cap for the Volkswagen Passat B7 features a screw-on design, which facilitates handling during daily refueling. Contoured edges improve grip, and the carefully selected body material ensures resistance to typical operational stresses, such as temperature changes, contact with fuel, or exposure to atmospheric conditions. Using a solution dedicated to Diesel fuel allows for compliance with the vehicle manufacturer's factory requirements.

Benefits of using an original cap

Choosing an original fuel tank filler cap for the Passat B7 translates into several practical benefits:

• secure, repeatable tightening thanks to the matched thread geometry,
• maintenance of filler neck tightness and reduction of contaminant ingress,
• compliance with factory requirements for the diesel fuel system,
• aesthetic fit to the fuel filler area of the Volkswagen bodywork.

For the user, this means stable operation and a lower risk of issues related to filler leaks, which is particularly important in modern diesel units sensitive to fuel quality. In the context of choosing a used part, it is worth emphasizing that the original component from disassembly retains its factory design parameters, which facilitates trouble-free installation.

Selection, installation, and operation

The cap is intended for use in the Volkswagen Passat B7 model and is compatible with the diesel fuel supply system. Installation consists of screwing the element into the fuel filler socket, without the need for modifying the neck or any additional alterations. In practice, this is a plug-and-play operation that can be performed by the user or during a standard vehicle inspection. Regularly checking the condition of the seal and the cap thread helps maintain stable operating conditions for the fuel system in the long term.

To better understand the role of the cap in the entire supply path, it is worth familiarizing yourself with topics related to the tank, pumps, and injectors – these are discussed in detail in the article Fuel system – injectors, pumps, and fuel tank: maintenance and regeneration, where you will find practical tips on diagnostics and operation.

Complementary Volkswagen fuel system components

If you are planning a comprehensive repair or upgrade of the fuel system area in your Volkswagen and need other components from the same group, such as filler necks, fuel supply lines, or tank mounting elements, check the available parts in the Volkswagen fuel tanks and filler pipes category.

When making a decision about choosing parts for the fuel system, a guide on repair strategies may also be helpful, discussing the differences between regeneration and purchasing used components – more information can be found in the material Regenerated or used original – which part to choose for repairs?. This will make it easier to assess when to opt for a used, original fuel filler cap and when to consider other service solutions.