BMW X3 3 5 Series E60 E61 E83 E87 E90 Fuel Tank Filler Cap Cover DIESEL 7786331

Visual condition of the part 

The product shows signs of use visible in the photos. 

BMW X3 3 5 Series E60 E61 E83 E87 E90 Fuel Tank Filler Cap Cover DIESEL is an original component from the Fuel filler flaps and caps category, designed for diesel fuel systems in popular BMW models. It ensures a tight seal of the filler neck, supports the proper operation of the fuel system, and prevents contaminants from entering the tank.

Specifications and technical data

• SKU: 7786331
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7786331
• Substitutable numbers: 7786331, 71227786331
• Fuel type: Diesel
• Category: Fuel Tank Caps

Purpose and technical function

The fuel filler cap in diesel-powered vehicles is responsible for maintaining a proper seal of the tank neck and stable operating conditions for the fuel system. In the case of diesel engines, this is important for:

• reducing evaporation and fuel loss,
• protecting against the ingress of water, dust, and other contaminants,
• maintaining proper pressure and venting within the tank.

The presented cap is a component dedicated to diesel-powered units, which allows for compliance with the requirements of the fuel system in specific BMW versions.

Compatibility with BMW models

BMW X3 3 5 Series E60 E61 E83 E87 E90 Fuel Tank Filler Cap Cover DIESEL has been designed for selected generations of the 3, 5, and X3 series that use a diesel fuel system. The precise fit of the thread, diameter, and seal geometry allows for installation in the factory filler neck without the need for modifications.

Thanks to this solution, the user maintains consistency with the vehicle's original design, and the cap works seamlessly with the existing fuel filler flap and body components.

Performance characteristics and installation

As an item from the Fuel filler flaps and caps category, the cap is intended for daily use in demanding road conditions. The construction adapted for diesel fuel ensures:

• a stable seal while driving and when parked,
• adequate resistance to diesel fuel,
• the ability to be unscrewed and tightened repeatedly without loss of functionality.

Installation is performed in the typical manner for original BMW caps – the component is screwed into the fuel filler neck, and its operation does not require any additional tools. This is a practical solution both for daily refueling and during fuel system maintenance.

Benefits of using an original Diesel cap

Using a dedicated fuel filler cap in BMW diesel vehicles translates into a number of measurable benefits:

• Structural compatibility – the cap is matched to factory filler necks in selected BMW models, which facilitates installation and daily operation.
• Support for the fuel system – a proper seal of the filler neck helps reduce the risk of contaminants entering the tank, which is crucial for the durability of injectors and pumps.
• Vehicle consistency – using a component compliant with the manufacturer's specifications allows for maintaining predictable fuel system behavior and ease of use.

Application area and selection of related components

If you are planning a comprehensive repair or upgrade of the fuel filler area in your BMW and need other components from the same group, such as additional caps, flaps, or mounting elements, check the available parts in the BMW Fuel filler flaps and caps category.

To better understand the impact of filler neck tightness on the entire fuel system, including the operation of injectors, pumps, and the tank, it is worth reading the technical guide Fuel system – injectors, pumps, and fuel tank: maintenance and regeneration, where diagnostics, part selection by part numbers, and principles of proper operation of fuel systems in diesel vehicles are discussed.